The Federal Aviation Administration said it will investigate an incident where the wing of a United Airlines Holdings Inc. flight clipped the tail of a Delta Air Lines Inc. plane at Boston Logan International airport on June 16.

The incident occurred while United Flight 369 was taxiing and Delta Flight 1657 was at a holding pad, the FAA said in a statement on June 18. Nobody was hurt.

“Customers on the United aircraft deplaned normally at the gate,” a United spokesperson said. Passengers were then rebooked on other flights. Six crew members and 128 passengers were aboard the United flight.

A Delta spokesperson said the airline “worked to get customers to their final destination as quickly as possible,” and apologized for the delay.

U.S. aviation has also seen repeated close encounters between planes this year. In January, an American Airlines Group Inc. wide-body jet rolled across a runway at John F. Kennedy International Airport in New York while a Delta flight was accelerating for takeoff.

The U.S. National Transportation Safety Board is investigating a near miss in February when a FedEx Corp. cargo jet came within 100 feet (30 meters) of hitting a Southwest Airlines Co. plane in Austin, Texas, and continued to stay in close proximity for at least 30 seconds.

The NTSB has been pushing for a wider rollout of aviation safety equipment that helps prevent collisions, yet industry experts have said a lack of resources makes this difficult to obtain. The system, which warns air-traffic controllers as planes and vehicles get too close to each other on runways, is in place at about 43 U.S. airports.

The National Air Traffic Controllers Association union has called on Congress to provide what it sees as its biggest challenge to reducing risk: funding.

Serious airport-runway close calls surged at the beginning of 2023, when at least eight cases involving airlines incited probes from the NTSB or were seen as high risk by the FAA. The FAA said there were signs near-crash incidents declined in March and April.