Joe Perry -- Grudging Acceptance of 'American Idol'

Aerosmith guitarist Joe Perry seems to finally get it ... Steven Tyler's gig on "American Idol" is good for the band.

Perry was at LAX yesterday when he was asked how he felt about Tyler returning to "A.I." as a judge. Perry replied, "It's tough having your lead singer have a day job .. but ya know, what can you do?"

But when asked if he would ever PERFORM on the show ... Perry said, "Yeah, that could probably happen."

It's a big change for Perry ... who slammed the show back in 2010 as an advertising machine that's only "one step above Ninja Turtles."