United Airlines planes parked at gates at Newark Liberty International Airport's Terminal C

In a move likely to be copied by other carriers, United Airlines has purchased used planes made by the Boeing Co. to make up for the expected shortfall in the loss of the 737 Max aircraft.

The purchases were revealed in United’s second-quarter earnings report – meaning the airline was prescient enough to recognize that the issues regarding the beleaguered 737 Max were going to last much longer than expected.

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In fact, some aviation experts and observers now believe the grounding could extend into the holiday season. The Boeing 737 Max was grounded in March after two separate crashes just three months apart on Lion Air and Ethiopian Airlines killed 346 people. Preliminary reports showed that a new stabilization system forced both planes into a nosedive from which the pilots could not recover. Boeing has been working on a software fix for the apparent problem.

But, the Federal Aviation Administration last month discovered another problem with the embattled aircraft – another flaw within the computer system was uncovered during a simulator test.

United said it has signed an agreement to purchase 19 used Boeing 737-700 aircraft, although it did not reveal which airline it is acquiring the planes from. That equipment is not affected by the issues plaguing the Max planes.

United and American have already announced cancellations of flights using the 737 Max through November – marking the fifth time the airlines, along with fellow U.S. carrier Southwest, have bumped back their deadlines awaiting FAA approval to get the Max planes back in the air.

While this is certainly a precautionary move, and it would be unsurprising to learn if American and/or Southwest follow suit, it’s not the first time United has purchased planes to increase its fleet. Last year, it bought 20 used Airbus 319 planes.