Originally Posted by
mixmastermark
If you put yourself in the right seat/plane, you *might* be able to carry it on.
In a similar situation, I easily brought a large painting framed w/glass (24"x36"x2" I think?) on board AS SFO-JFK.
I strategically confirmed myself in window seat 2A (or 2F works the same) in F on a pre-retrofitted Airbus. There is an incredibly generous, wide space to securely slip a painting between the seat and the window in the second row of first class on those planes.
Whether someone will stop you before you get to the plane, is up for debate, but there is space for it. Not sure if 30" is too wide for the TSA X-ray belt or not.
Another potential space is the coat closet in F on the 737s. They are usually 40" tall, not sure if they're 30"+ deep though.
Best of luck!
Storing it along side the seat is not considered proper stowage so technically nothing can go there. The coat closet could work but assistive devices get first crack at the closet. If it’s full they could end up asking the OP to check the painting and I don’t think that’s a great idea.