Friday afternoon experienced delays due to an unspecified security reason, according to the Federal Aviation Administration (FAA). READ MORE | NTSB: Helicopter may have had technical issue before deadly DC midair collision near DCA Before 4 p.

The Federal Aviation Administration plans to reduce the number of flights at the highly congested Reagan National Airport to address safety concerns in the wake of last week's deadly collision between a regional jet and a U.S. Army helicopter, Reuters reported Thursday.

All runways at Reagan National Airport outside of D.C. reopened, with plane activity slowly returning to normal several weeks after the deadly midair collision.

Officials want to permanently keep helicopters away from commercial jets taking off and landing at a busy Washington, D.C., airport after the deadliest U.S. aviation accident in more than two decades.

Ronald Reagan Washington National Airport reopened two runways following the Jan. 29 American Airlines flight and helicopter collision that killed 67 people. “Runways 4/22 and 15/33 at Reagan Washington National Airport (DCA) have reopened and we have increased the hourly arrival rate to 28 aircraft,

According to an email sent to airlines, the FAA is temporarily reducing the number of planes that can arrive each hour at Reagan National Airport (DCA).

Federal safety officials want to permanently keep helicopters away from commercial flights at Reagan National Airport.