Hanscom Field, Bedford, Mass., is now a gateway airport for companies that want to fly into Ronald Reagan Washington National Airport (DCA). The Transportation Security Administration (TSA) permits corporate and charter flights to use DCA with certain restrictions, including arrival from one of 19 gateway airports, vetting of flight crews, screening of passengers and carriage of an armed security officer on board. The TSA also altered DCA’s hours of operation, and since March 5, approved operators can use DCA between 6:30 a.m. and 10 p.m., the same hours as the airlines. Slots are still required from 7 a.m. to 6:59 p.m., but outside those times a slot is not required, according to the TSA.