921st CRS Airmen work alongside 60th APS, maintain proficiency through COVID Published July 7, 2020 By Tech. Sgt. David W. Carbajal 621st Contingency Response Wing TRAVIS AIR FORCE BASE, Calif. -- Members of the 921st Contingency Response Squadron aerial port flight have been maintaining their proficiency in air transportation duties by working alongside the 60th Aerial Port Squadron since June 2020.