In a state of panic and fearing catastrophe, I am writing this midflight as I travel from Calgary, Alberta, to Los Angeles on American Airlines.
I thought I did everything right: bought two seats, a ticket for myself and one for my Andrea Guarneri cello made in 1669. I checked in, got two boarding passes, and went to the boarding gate without problem. It all went smoothly — the cello and I were even pre-boarded — one of the easier of the literally thousands of flights we have taken together. Until . . .

Comments
This sounds like an opportunity to develop sturdier, more protective cases for large, rare, expensive musical instruments. Of course, in a crash, it would not survive, but rail, road, and ship are slow by comparison.
Did he get refunded his $$$ for the ticket he bought for his cello??
Hmmm, but they allow unrestrained BABIES UNDER 2, who also are unable to hold on, and who, in the event of turbulence, will, unlike the secured in a seat belt cello, become projectiles. Idiocy.
I have had my trombone (while packed in a hard case) damaged in baggage by aircraft. Also, a french horn I was transporting for a friend. While both are less expensive than your vintage cello and a dent in a brass instrument is more easily repaired, I still feel your pain.
I do feel for Mr. Katz and his dilemma. I don't understand why he can't pay for a second seat - i've seen people do it with small cartons, although it's been a while since I've seen that. But I have experienced passengers bringing guitar cases on board, and managing to pre-board. Then they proceed to take up an entire overhead bin with the instrument, forcing three other passengers to scramble for other space...inevitably, someone then winds up having to check their bag. Too bad the airlines can't make space for these instruments in the cabin. Cello and tubas, maybe not, but guitars in slim cases, yes.