There is no federal law about forcing injections.
It’s something Senile Joe is doing without any legal authority, just like the Kenyanesian Usurper made up DACA out of thin air.
Unfortunately, the EO on contracts is something the President has the power to do. No company needs to renew their new contract with this added clause.
I read somewhere that SWA only receives about 3% of its revenue from Federal contracts so the question becomes, “why would they risk losing 30% of their flights by forcing the vaccines?”