AITA for letting my sister and her family handle flight cancellation by themselves

I just came back from a 2 week vacation with my sister, her 4 year old and a 1 year old. They're visiting from abroad and I took them to various cities around the us, LA, NY, Disney Orlando and where I live. I booked all the plane tickets and everything else we needed to get around I basically took responsibility for including booking rides hares or renting a car and driving them around all these places. Something that kept happening was that we seemed to always be tight on time. Everytime I pushed to get us on time it always leads to a big argument or issue on how I can't understand because I don't have kids. Even when I say we'll leave at this exact time and give the time a day before even. We still ran into this problem. Today we ran late again for one of our flights. We could've made it if we moved quicker but my sister's family aren't really great at it. I didn't push because I didn't want to cause another fight. I honestly thought we might make it but we were really cutting it close with how slow we were moving. Turns out we needed to take a bus to our terminal so at that point I knew we wouldn't be able to make it anymore but just let it play out. We get to the gate and boarding is closed. I sat there and just had them deal with finding guest services and rebooking the flight. I just hung out with my nieces while they waited in line. Once we got the tickets rebooked and we're at the gate, I fell asleep and didn't wake up until boarding time, they had to handle scanning boarding passes.

Next thing I hear is my sister saying to her husband how not big of a deal it is to do that stuff that it's just knowing how to do it. That when they're relying on someone that's when it's a big deal bla bla bla, I think essentially saying since I didn't do it, shame to me they get it done inspite of me and all that. Now everyone has an attitude and they're all of a sudden pulling their kids away from me.

AITA for making them deal with this one time after chauffeuring them everywhere and taking care of everything else during their visit.