Southwest Airlines is experimenting with letting passengers board through the front and rear of their planes at the same time. Will it help speed up boarding and improve on-time departures and arrivals? We’ll see.

Some of us are old enough to remember the Boeing 727, a three-engine workhorse airliner with a built-in ramp in the tail. Passengers could board simultaneously at both ends of the airplane.

That all came to an end in 1971 when an infamous airline hijacker used a 727’s rear stairs to parachute off the plane with $200,000 in extorted loot.

Almost a half-century later, front and rear passenger boarding could be poised for a comeback.

Travel industry media are reporting that Southwest Airlines plans to experiment with simultaneous boarding at four California airports – Burbank, Long Beach, Sacramento and San Jose. The Boeing 737s that comprise Southwest’s entire fleet have no rear ramp of their own. They do have a rear door, however. So passengers will be able to board through both ends of the aircraft at the same time.

So while some passengers will be walking through the jetway to board at the front, others will have the option of walking downstairs and out across the tarmac to use stairs at the back.

Airlines are under a lot of pressure these days to have their flights arrive and take off on time — from governments, from airports, and especially from the flying public. If you ever took a trip that depended on catching a connecting flight, you know why.

And at present, Southwest’s on-time performance leaves more than a little to be desired.

The Official Airline Guide ranks the world’s airlines by the percentage of their flights that arrive on-time, ranking them from one star to five stars, with five being the best. Southwest’s on-time percentage came in at 78 percent, which put them in the 3-star class.

Definitely not the worst, but nothing to brag about, either.

(For the curious, only one US-based airline — Hawaiian — was in the 5-star class. Alaska, Delta and United airlines were good enough for four stars. JetBlue brings up the rear with 70 percent, no better than two stars.)

Airlines in other parts of the world already do this. I experienced it first-hand earlier this year while traveling in Vietnam. I didn’t time it with my iPhone stopwatch, but the process itself seemed to go smoothly. So we’ll see how Southwest fares with it.

It will be especially interesting to see what happens when the front-boarding passengers, especially latecomers, try to find luggage space at the back for all their carry-ons.