This is bullshit. Adobe had a negative space verion of the a, but never used anything that looks like this until very recently. Meanwhile Delta has beem using this logo for well over a decade.

Also, it's a pretty generic logo that probably shouldn't be trademarkable. (the earlier negative space version, sure, but not what amounts to basically just a triangle)

It sucks that corporations can basically just decide that something is theirs now, and force everyone else to stop using it.