Maximusno2: You've already received some great advice; so I don't have much more to add to that. One thing I will say is that it's a lot easier than you may think it will be. Security (on the USA side) is usually not a concern. If you can use a pull up to get thru security and then change into something more appropriate, then that will be better. If not, the worst that can happen is that they will do further investigation since wetness shows up in a body scanner. Of course, a standard "metal scanner" won't flag wetness. This is the main reason why I will I
always opt-out of a body scanner if they are going to force me into a body scanner. Of course if they don't force me into the body scan line, then all the better for me!
As mentioned, keep very well hydrated. It's been said a person should drink 1 liter of water for every hour of flight because a plane is typically kept at less than 15% humidity! If you do that, then you will need to change on a long haul flight. And even though an airplane's loo is tiny, changing and disposing has never been an issue for me (even in turbulence!

).
I tend to pack enough diapers and accessories to get me thru 24 hours. This is "just in case" something goes wrong and there are interminable delays or misplaced luggage.
Lastly, keep in mind that in LA and the States, premium diapers are not easily found in our average, general retail shops. We tend to sell very low end, low capacity diapers at the retail level. So I would suggest you keep a list of medical supply stores (which should carry better, premium diapers) near your touring locations.
Best Wishes and Enjoy My Country!
ILuvLA.