Didnt read all the comments but it seems that if you have 2 bags , the second a kite you'd be charged $25 for the first and $150 for the second. Many airlines would charge you $25 for first, and $35+$150 for the second

+1 for loco. Im on my way to pr right now with a 29" bag containing my self made split board , harness 2 kites, and 2 bars

Good info about Delta, Thx for sharing.

Keep it under 50 lbs is important, they may overlook the size but never the weight

Most airlines will offer you free checked baggage if you fly first class so here is what I have started doing. If first class is available I see what the fare difference is between my currently priced ticket and what they are going to charge me for my kite gear. If the cost to upgrade to first class is less than the cost to check my kite gear then I upgrade to first class.

So I actually save money AND get a much better seat. I've done this 3 times now.

One last resort I have done is simple creative negotiating at check-in time. I always do curb side check in because the guys outside work for tips. One time the guy at curbside check-in was going to charge me $150 for my kite gear and I asked him if he would check it as a regular bag and not gig me for the extra money I would tip him $50. He did it and I saved $100.

Ehhh? That's something you need to explain please. Those upgraded flights where you saved some bucks were short distance flights and not Intercontinental flights, correct?
The fare difference on Intercontinental flights are many thousands of $$$s and for that sort of money you can transport a lot of gear (or take a few buddies of yours into "Golf Bags").

Cheers
Caesar