I love it jimbocz!
In all seriousness, thanks for the advice you've all given me today. I posted on here mostly thinking I'd be venting to myself a bit!

This specific situation is part of an ongoing power struggle with my parents since I left home for college over a decade ago. They're always wanting me to visit more, with me doing most of the visits. The times I've obliged their desire to see me more has only made them get pushier and demand
even more visits. Aunts and uncles get in on the "fun" sometimes, too. I've mostly gotten used to saying no and just dealing with the enormous guilt I feel when my mom snaps on the phone, but I'm aware a sibling marriage is a very important occasion.
As for this wedding, we do hope to make it a quick trip, arriving maybe 2-3 days before the event and heading out the day after the festivities. From all of your feedback, I've decided to ask my parents, who care more than my sibling about me being there, to help my spouse and me with the cost of airfare. And we definitely won't be flying to anyone for the holidays this year!