An off-duty pilot travelling as a passenger stepped in to provide assistance after the airline captain suffered a mid-air medical emergency.

The Southwest Airlines flight 6013 from Las Vegas to Columbus in Ohio on Wednesday returned to the departing city two hours after takeoff when one of the pilots became incapacitated and required “medical attention”.

A pilot from a different airline who was on the flight reportedly provided assistance with radio communication while the other Southwest pilot took control of the aircraft.

The aircraft flew over Utah north of the Grand Staircase-Escalante National Monument before eventually returning to Las Vegas.

“The flight landed safely, and an alternate flight crew is operating the flight to CMH (Columbus),” Southwest said in a statement.

“We commend the crew for their professionalism and appreciate our customers’ patience and understanding regarding the situation.”

The FAA on Wednesday issued safety alerts to airlines, pilots and others about the “need for continued vigilance and attention to mitigation of safety risks” after a series of high-profile near collisions.

“While the overall numbers do not reflect an increase in incidents and occurrences, the potential severity of these events is concerning,” the FAA said.

The agency convened a safety summit last week following six serious runway incursions that have taken place since January.

The National Transportation Safety Board is investigating a series of serious close calls, including a near collision in February between FedEx and Southwest Airlines planes in Austin, Texas, where the jets came within 100ft of each other, and a runway incursion at New York’s John F Kennedy Airport involving an American Airlines aircraft.

According to reports, a Southwest Airlines jet came within feet of slamming into an ambulance crossing the runway as it took off at Baltimore’s airport in yet another incident.

The Aircraft Rescue and Fire Fighting (ARFF) vehicle crossed Runway 15R at Baltimore-Washington International Thurgood Marshall Airport without authorisation, DC News Now reported on Tuesday.

The Southwest Boeing 737 aircraft was cleared for takeoff from the same runway and missed the ambulance by “less than half the length of a football field”.

“The closest estimated horizontal separation occurred at a distance of 173 feet,” the Federal Aviation Administration (FAA) said in its analysis.