Ryanair , the Irish budget airline, said on Tuesday that it would scale back its growth plans for next summer because of expected delays in taking delivery of Boeing 737 Max planes.

The airline, which has grown quickly by offering inexpensive flights to smaller airports across Europe, had ordered 58 of the planes for delivery by next summer. But four months ago, after the 737 Max was involved in two fatal crashes, regulators ordered the aircraft grounded.

Boeing is updating the plane’s software to get regulatory approval so the 737 Max can fly again, but the grounding was extended after the Federal Aviation Administration identified a new problem with Boeing’s emergency procedures . Until the problem is resolved, airlines that ordered the planes cannot take delivery of them.

“Ryanair remains committed to the B737 Max aircraft, and now expects it will return to flying service before the end of 2019, however the exact date of this return remains uncertain,” Michael O’Leary, the airline’s chief executive, said in a statement.