Before the additional flights were approved, a senator warned that the increase could heighten the risk of collisions.

An airspace cluttered with passenger planes and military aircraft. A history of near-crashes. And a growing shortage of air traffic controllers available to manage it all. Some experts, politicians and airport managers have been warning for years of the risks posed by the crowded airspace and volume of flights at Ronald Reagan Washington National Airport (DCA).

Wednesday’s crash has resurfaced concerns about the airport’s proximity to the river, narrow landing space and overcrowding. Despite the geographic and logistical challenges, Congress authorized 10 additional “slots,” or flights, to DCA’s daily flight schedule.