I just had a friend that flew United, was going to a honeymoon in Argentina. Got caught up in the problems from the past week, they delayed his flight by 6 days (all the rebookings filled up every day going forward)! They refused to compensate him. He had to cancel the whole thing and they wouldn't give him a dime. How is that legal? They claimed it wasn't their fault, so it's not their responsibility to refund. I told him to at least try to get compensated with points (which they will normally do, but it can take a month+ for them to do it and requires a lot of bitching.)
I've had my flight delayed by 36 hours before and AmEx did a full claw back of the fare, since I missed a major event I was going to. If I hadn't had AmEx I'd have been SOL. The Airline in my case also claimed it wasn't their fault as well, though we had a 4-hour delay before because of a landing gear problem. They blamed it on air traffic control and said they couldn't do anything to refund me. Very lucky AmEx thought otherwise, otherwise I was out $2k. The airline industry is getting away with murder, which considering they've been saved by the government several times at this point is just infuriating.
Although I wrote about Article 19 of the Montreal Convention below which would have applied in your case, I should point out that in practice as a heavy traveler I mostly also rely on AmEx. AmEx has saved my bacon so many times I've lost count, in one case they basically literally saved my life by providing me a translator and guaranteeing my deposit to be treated in a hospital for 4 days while I was traveling in a foreign country one time. They've helped cover damage to rental cars, and flight cancellations, and all sorts of other things throughout the nearly 20 years I've had my card.
While knowing the law is a good thing, I honestly think for us Americans the most important thing is having a competent travel card and knowing what your coverages are and using them. AmEx is a godsend when dealing with shady airlines, rental companies, and hotels.
As much of a bad rap as credit cards get (and rightfully so in many cases) having a good travel card is essential if you travel relatively often. I think Capital One is fairly good about this type of thing as well. That being said...such a thing shouldn't be required for most of these instances. Airlines are just screwing people. I understand the frustration people have. I've been lucky to only ever have had minor delays (sans my example,) but people that get really screwed over have every right to be angry and demand the FAA do something.
You don't need a credit card for that. The travel insurance is just a perk with some US cards (EU cards have very few perks!). You can also get it if you just pay for it.
I have a mandatory amex card from work (in my own name no less) and I hate it, because it's so useless in Europe. Taxis often refuse it (or the reader is suddenly 'broken'). Apparently they charge much higher commission than the others, one driver told me. Restaurants frown at it. Shops don't even accept it. The only place it works reliably is hotels. I'm sick of having to use this thing and my work makes a fuss if I use my own local card for work trips. Some exec in finance probably gets a great kickback for that rule.
For going to the US it's apparently great but I've never been there in my life and in Europe it's really tough. Especially Eastern Europe where they just laugh in your face when you pull it out but even in the taxi queue at Charles de Gaulle Paris you really have to beg to get a taxi to accept it.
And I don't think the corporate version comes with the travel insurance. Because we have international SOS for that. They wouldn't have got that if it wasn't needed because they aren't cheap. Which is something I do have very good experiences with in all my corporate travel by the way. The few cases where I've seen colleagues need it their service has been exceptional.
I've had my flight delayed by 36 hours before and AmEx did a full claw back of the fare, since I missed a major event I was going to. If I hadn't had AmEx I'd have been SOL. The Airline in my case also claimed it wasn't their fault as well, though we had a 4-hour delay before because of a landing gear problem. They blamed it on air traffic control and said they couldn't do anything to refund me. Very lucky AmEx thought otherwise, otherwise I was out $2k. The airline industry is getting away with murder, which considering they've been saved by the government several times at this point is just infuriating.