Currently, foot-launch tandems ARE allowed in the U.S. with a certification by USPPA.org and two other orgs. There is no cost from the organization beyond annual membership dues of around $40 / month. In fact, anyone who gets their instructor rating is entitled to $100 training reimbursement while funds last.
Wheel-launch tandems are also allowed in the U.S. under those programs. They started being allowed in 2018 after many years of prohibition.
For all training information, go to the Schools and Training page of USPPA.org.