At least one lawmaker is said to be considering legislation that could raise the federally-mandated retirement age for airline pilots from 65 to 67 or higher to extend aviators’ time in the skies.

A regional airline proposed reducing flight-hour requirements before joining a U.S. carrier, and airlines are rethinking training programs to lower the barrier to entry. Earlier this year, Delta Air Lines joined other big carriers in dropping a four-year degree from its pilot hiring requirements.

Several U.S. airlines, including Frontier, are recruiting some pilots from Australia. American Airlines is selling bus tickets for some short routes.

But some airline executives warn the shortage could take years to solve.