American Airlines Group Inc. managers will fly on Boeing Co. 737 Max aircraft before paying passengers are asked to climb aboard—a move meant to build confidence in the plane’s safety.Executives and other staff will join American pilots on flights as soon as regulators certify that the Max is cleared for travel, and before Sept. 4, which is the earliest date commercial trips will resume, American Chief Executive Officer Doug Parker said at the carrier’s annual shareholder meeting Wednesday. The Max has been grounded worldwide since March 13, after two fatal crashes within five months.

Airlines have been crafting strategies to convince travelers the Max is safe now that Boeing has improved software for a flight-control system that malfunctioned in the accidents and bolstered the fixes with new pilot training. U.S. safety regulators have said they’ve set no time frame for signing off on Boeing’s proposed repairs for the jet.

“We’d like to get it flying again so when customers get on it, they realize it’s been flying potentially for weeks,” said Ross Feinstein, a spokesman for American. Airline executives, managers, flight attendants and other employees could be among those aboard, he said.

American earlier this month tacked two weeks onto the time the Max will remain off of its schedule, extending its absence through Sept. 3. The change was made to accommodate crew scheduling needs, and doesn’t mean the airline doubts the Max will be approved to resume flights earlier, Parker said.

“We wouldn’t be selling seats today if we didn’t think it was a highly likely possibility that the aircraft will be flying by Sept. 3,” the CEO said.

The first post-approval flights, which will include those needed to shift some grounded planes from storage in Roswell, New Mexico, to American’s maintenance base in Tulsa, Oklahoma, can also be used as a refresher for pilots whose training has been updated.

“Once you see pilots from American, Southwest and United saying they’re taking the plane up because it’s safe to fly, it will be,” Parker said. “They are exceptionally well trained, they are safety professionals.”

United Continental Holdings Inc. has removed the Max from its flight schedule through Aug. 3, while Southwest, the biggest Max operator, has set Aug. 5 for its return.