Meet the VFS staff

The Vertical Flight Society staff is extremely lean but efficient. The following descriptions indicate the basic areas of responsibility for each member of the VFS headquarters staff. Any questions that you may have can be directed to the staff member who covers that area. You can contact us at +1-703-684-6777 — our extensions are listed below.

Angelo Collins
Executive Director, x120

Angelo CollinsAngelo Collins assumed the duties of the Vertical Flight Society Executive Director in June 2023, after 15 years in the aerospace industry, primarily in vertical flight. As the VFS Executive Director, he represents the vertical flight technical community and advocates for the advancement of vertical flight research and technology.

Angelo was previously an employee of Booz Allen Hamilton, where he supervised a team of engineers and analysts supporting numerous cutting-edge programs in DARPA’s Tactical Technology Office (TTO). He supported numerous vertical flight-related programs for DARPA, the Office of Naval Research (ONR) and the F-35 Joint Program Office (JPO). As a program manager for Skyworks Aeronautics, Angelo led a team of international engineers, analysts, and lawyers in the development of an electric gyroplane. A member of VFS since 2008, Angelo served as the Administrative Chair of the first VFS Transformative Vertical Flight (TVF) Workshop in 2014, the world’s first meeting of the emerging eVTOL pioneers. 

Angelo has a BS in Aerospace Engineering from the University of Maryland (UMD) and an MS in Engineering Administration from Virginia Tech. He is a native of the Boston, Massachusetts area, but has lived and worked in Arlington, Virginia, for 15 years, where he resides with his wife Nicole, daughters Camila and Aria, and son Loukas.

Mike Hirschberg
Director of Strategy, x111

Mike Hirschberg Mike assumed the duties of Director of Strategy in June 2023, after 12 years serving as the VFS Executive Director. 

Prior to joining VFS in 2011, he worked for 20 years in the aerospace industry, primarily in vertical flight. Mike was previously a principal aerospace engineer with CENTRA Technology (now Amentum), providing technical and program management support for over 10 years to the Defense Advanced Research Projects Agency (DARPA) and Office of Naval Research (ONR) on advanced aircraft and rotorcraft concepts. Prior to this, he worked from 1994 to 2001 in the Joint Strike Fighter (JSF) Program Office, supporting the development of the X-32 and X-35 vertical flight propulsion systems. Mike also served as the Managing Editor of Vertiflite magazine from 1999 to 2011, and had been a contributing author since 1997. 

Mike holds a BS in Aerospace Engineering from the University of Virginia (1991), a Masters of Mechanical Engineering from Catholic University of America (1996) and a Master of Business Administration from the Virginia Polytechnic Institute & State University (Virginia Tech) in 2013. He is an Associate Fellow of the American Institute of Aeronautics and Astronautics (AIAA) and a Fellow of the Royal Aeronautical Society (RAeS).

Julie M. Gibbs
Director of Technical Programs, x103

Julie M. Gibbs originally worked for VFS as the Director of Membership (1999-2005) after 12 years in the Washington, DC, offices of GKN Westland (now Leonardo) working as the Marketing and Meeting Manager. In more recent years, Julie worked as a Communications and Event Manager for a naval defense contractor and as an Executive Administrator supporting VP level management for an international IT technology service provider. She rejoined the Society in May 2016.

As the Director of Technical Programs, Julie is the principal liaison with the Vertical Flight Society technical community, supports the VFS Technical Director and all Technical Council meetings, and is the production manager of the Journal of the AHS. Julie also works closely with the Forum Technical Chair to coordinate the Forum’s technical sessions, and coordinates the Forum student volunteer program, and supports with the Technical Committees with planning and executing their Technical Meetings and other activities.

Julie is also the point of contact for awards established/reviewed by the Vertical Flight Society Technical Council, including the Vertical Flight Foundation (VFF) Scholarships, the Robert L. Lichten Competition, the Alfred Gessow Forum Best Paper Award and the Student Design Competition.

David Renzi
Director of Meetings and Advertising, x105

David Renzi joined the Society in February 2002 and he is the principal coordinator of the Annual Forum, the largest event of the year for the Society. He conducts all technical exhibit sales and coordinates the exhibit hall floor and sponsorships. He also administers the subcontracting for Forum activities including convention and hotel services, tours, special events, transportation, and entertainment.

David works with the Director of Membership in the coordination, planning and scheduling of the Annual Forum and bi-annual Board of Directors meeting.

He is also the principal advertising contact for Vertiflite magazine, the Vertical Flight Society website, and all Forum-related publications.

Valerie Sheehan
Director of Membership, x107

Valerie joined the Vertical Flight Society in July 2015, with nearly 25 years of prior experience in international non-profits and membership associations, including the World Bank, World Resources Institute and, most recently, with the National Association for the Education of Young Children (NAEYC).

Valerie is responsible for all aspects of the Society’s membership including day-to-day membership management, recruitment/retainment, member services, development and marketing, financials and membership communication. She is also the primary liaison to all VFS chapters, and oversees the VFS’s annual awards program. 

Valerie is a graduate of the University of Toronto and is fluent in French.

Randy Johnson
Director of Information Resources, x104

Randy Johnson joined the Society in October 2007. He is the Society’s in-house IT specialist and is responsible for all network and systems administration. He is also the Society’s webmaster, and together with the Director of Membership is responsible for configuration and maintenance of the Vertical Flight Society membership database.

Tom Risen

Managing Editor of Vertiflite magazine, Director of Media and Marketing Operations

Tom Risen joined VFS in 2024 as the managing editor of Vertiflite magazine and has now taken over additional responsibilities. Online marketing duties include managing social media, writing and web production of the “eVTOL News" newsletter, along with video management and scheduling for several of the Society's working groups.

Tom previously has reported on aviation business and technology news for Cirium, FlightGlobal, Aerospace America, and U.S. News & World Report.

Betty Chen
Academic Coordinator, x102

Betty Chen joined the Vertical Flight Society staff in August 2014 after serving in technical and administrative roles in the US, China and Argentina. She is fluent in Mandarin and Cantonese and is proficient in Spanish.

Betty is the Vertical Flight Foundation (VFF) Scholarship Fundraising Coordinator and the primary point of contact for students and for chapter development activities, and developing the Society's science, technology, engineering and mathematics (STEM) outreach and content. Betty also assists with graphic design, marketing activities, and website design, and serves as the Annual Forum Registrar and Asia-Australian Region development coordinator. She is also the principal point-of-contact for purchases of proceedings, technical papers, books and Vertical Flight Society novelties.

Alka Rathod
Administrative and IT Assistant, x100

Alka Rathod joined VFS in March 2019. As the Society's Administrative and IT Assistant, she keeps the Society's website up to date, manages the Vertical Flight Library & Online Store, provides database support and has taken on expanded administrative work with an increase in the Society's membership and vertical flight activities. 

Alka previously worked for more than 25 years in New Delhi in various government departments.  She acquired her studies in India. She is also fluent in Hindi, Punjabi and Gujrati languages.


Consultants & Advisors

In addition to the incredible volunteer contributions of the VFS membership, the Society has a wide range of consultants, advisors and assistants around the world, from leading major initiatives to writing and editing our Vertiflite magazine. A few of our most important advisors and consultants are listed below. 

Rex Alexander
Advisor for VTOL Infrastructure

Rex Alexander has over four decades of military aviation, general aviation and commercial aviation experience, and is a globally recognized subject matter expert on helicopter, vertical lift and eVTOL infrastructure. He is the founder and president of the aeronautical consulting firm Five-Alpha (5α) and has served as Infrastructure Advisor to the Vertical Flight Society since January 2019.

He is co-chair of the US Helicopter Safety Team (USHST) Infrastructure Working Group, Chair of the National Fire Protection Association (NFPA) 418, Standard for Heliports, a member of ASTM International F38 WK59317 New Specification for Vertiport Design, a member of the Vertical Aviation Safety Team (VAST) Technology Working Group, a member of the Illuminating Engineering Society (IES) Technical Committee, a member of the Helicopter Association International (HAI) Vertical Flight Infrastructure Sub-Working Group.

Rex is an alumnus of Parks College of Aviation and a former US Army Warrant Officer and ‘Aeroscout’ Helicopter Pilot, Instructor Pilot and Standardization Instructor, having served both on active duty and in the Indiana Army National Guard.


The Vertical Flight Society 
2700 Prosperity Ave., Suite 275
Fairfax, VA 22031-4340 USA
Phone: +1-703-684-6777
Fax: +1-703-739-9279
Email VFS

Updated Sept. 26, 2024