Are there more than 3 teams in the USA? What do you get if you qualify?
The AMA pays for the entry fee and housing and meals during the duration of the Championships. There is an allowance provided that generally does not come close to pay for the plane ticket to wherever. Other transportation costs, like a car or sharing a car with another team member or team members, housing/meals for days not during the competition, uniform costs, fuel (whatever you use - bring your own which is a major problem or purchase standard ingredients ordered prior to the contest from the organizers, make arrangements to have fuel delivered which can be another major problem), batteries and their transportation (which can be a major problem), etc, are all out of pocket. Sometimes, the SIGs provide some financial assistance. Also, some team organizers will have fund raising programs like selling team shirts, hats, patches and/or outright donations. This is not a joy ride paid for by the AMA and the SIGs.
The AMA is also placing a premium on team performance. The AMA can decide that if the collective performance of teams in a specific event over some period does not meet some "standard" in the world competitions, then the AMA will no longer sponsor a US team in that event. That has not yet happened in any of our control line events -F2A, F2B, F2C, or F2D. I do not know about any of the multitude of other team events regarding this.