WOOD DALE, Ill. (AP) -- Aerospace supplier and service provider AAR Corp. said on Thursday that it amended its deal with Mesa Air Group Inc. for parts and maintenance for Mesa's CRJ-200 and ERJ-145 aircraft.

AAR said the deal gives Mesa more flexibility to respond to demand changes for 50-seat planes. Planes of that size have fallen out of favor with airlines because of higher fuel costs.

In exchange, Mesa is paying AAR 15 million common shares (worth about $2.3 million based on Thursday trading at about 15 cents per share). AAR is returning to Mesa $6.1 million aggregate principal at maturity of Mesa 2023 notes.

AAR said it may sell its Mesa shares from time to time.

AAR said it has generated about $30 million in annual sales supporting the Mesa CRJ-200 and ERJ-145 planes.

AAR shares rose 66 cents, or 3.4 percent, to $20 in midday trading.