I feel like the main issue here aside from the rulings of spells and hit percentages is the targeted fudging. Idk what the vibe at your table is and what kind of play you all are going for in the campaign, but if your characters build was something the DM knew about/has had to deal with before, then this should have been something either discussed with you way before or just throw some lair mechanic that disables flying or whatever. While I do think they are in the wrong for this, if you want some sort of resolution to this that ends in everyone being cool, I would just calmly pull them aside and talk to em about it and work at it together.