American was the only major airline not represented -- even UPS and FDX were there. It's doubtful it mattered too much given the lack of substance that was discussed (nothing on Norwegian or the ME3, just airports and ATC modernization), but it was a chance for face time with POTUS, which is a rarity unless you're a serious donor like Jeff Smisek was with Obama (and look how that ended...).
What is a fact is that Trump can now place a name and face with Ed from DL, Gary from WN, Robin from B6, Oscar from UA, and Brad from AS.
When someone mentions Doug from AA? That will draw a blank, or perhaps "Oh yeah, he didn't come like everyone else did."
Someone, even Isom or the head of Government Affairs should have been there.