The very last US Airways flight takes to the sky on Friday.

By most measures, the airline has already been absorbed into American Airlines, but Friday night marks the final flight: Flight 1939 will leave San Francisco at 9:55 p.m. PT and arrive in Philadelphia — in a state where the airline's history dates to 1939 — the next morning at 6:18 a.m. ET.

The plane will leave Philadelphia earlier on Friday in a festive tribute to cities meaningful to the history of the carrier. The Airbus A321 will depart Philadelphia for Charlotte, N.C., at 10:05 a.m. ET, depart Charlotte at 2:35 p.m. ET to fly to Phoenix, then fly on to San Francisco at 5:10 p.m. PT, and then leave on its final red-eye.

US Airways started operating flights under that name in 1997. Before that, it was USAir, Allegheny and All-American Aviation, which got its start in the airmail business in Pittsburgh in 1939.

Among the passengers on the last leg will be 89-year-old Edwin Colodny, who was CEO of USAir from 1975 to 1991: "It's nostalgia," Colodny said.

"Having been involved with the creation of the USAir name back in the 1970s, and being so involved with the company for 40 years, I thought it would be neat to fly the last flight under that name."

@MD80com @USAirways here's a look back in history at the #longbeach plant when DC-9's where made brand new!!! pic.twitter.com/ixRDz37Nkj — Chad Buckwalter (@chad5286) June 15, 2014

Airline mergers are common in the industry's history, but consolidation has been more obvious in recent years. In 2000, the U.S. had 10 major airlines — there are now four: American, United, Delta and Southwest.

It has been two years since American started to fold US Airways' operations into its own.

On January 30th, 2014, the first US Airways aircraft (N700UW) was painted in the new livery. #RememberingUS (AA pic) pic.twitter.com/hBfgZFnGUe — AirlineGeeks.com (@AirlineGeeks) October 15, 2015

Painting the planes is only the most obvious part of the switchover: Booking systems, crew schedules and more have all been slowly combined in different phases. The US Airways' call sign was retired in April.

The us airways name is fading into history pic.twitter.com/D1Mba4mpdi — Daniel Stone (@skyguystoner) September 23, 2015

Tomorrow, US Airways flies into history. pic.twitter.com/RfP6XXIYoP — Miami Int'l Airport (@iflymia) October 15, 2015

US Airways had many memorable moments in history, but few stand out as clearly as the 2009 emergency landing of Flight 1549 on the Hudson River, in New York City. All 155 passengers and crew survived, as ferries and emergency vehicles made their way to the plane in the river.