concerning the boots:
- Many airlines group a boot bag and ski bag together when regarding checked baggage. You will probably pay oversize for the skis but (check with the airline obviously) you probably won't pay any more for boots.
THAT BEING SAID
- I personally would take my boots carry on. Your boots are custom fit to your fit and finding a replacement in the case of lost baggage is a lot worse for boots than skis. Last year I flew with all my ski stuff twice. I packed my boots (strapped as tight as possible) in my carryon luggage. They are smaller than you think. Then i packed as many clothes as I could around them and stuffed the rest (including ski clothes) into my ski bag. It will fit. And your skis will be protected. Wrap shirts, jackets, whatever around your bindings and tips.
- Also, invest in a bag that will be about the maximum size for carryon, specially made so. Instead of worrying about finding a bag that will fit all of your stuff while at the same time being small enough for carryon, just buy a purpose made bag.
Here's a $75 dakine bag through backcountry that is similar to the one I have.
http://www.backcountry.com/dakine-carry-on-roller-1900cu-in?CMP_SKU=DAK1712&MER=0406&SKID=DAK1712-BKA-ONESIZ&CMP_ID=PLA_GOc001&mv_pc=r101&mr:trackingCode=019233EE-E0CE-E211-AFFE-BC305BF82376&mr:referralID=NA&mr:adType=pla&mr:ad=42743343945&mr:keyword=&mr:match=&mr:filter=62930413905&origin=pla&gclid=CPDGx4TvqLkCFUui4AodSFIAdA
Good luck, flying sucks these days