What I've read indicates that is a miss-characterization of the underlying dispute. Both sides seem to be pointing to a change in the rules (as passed by the Republican controlled house) for how unionization vote passage is to be determined. [As I understand it: It currently is majority of all votes cast; new rule as set out by house Republicans would change it to a majority of all eligible workers, with non-voting workers counted as "no" to unionization.] The Democratically controlled house and the administration are sufficiently opposed to this rule change to prefer shutdown of the FAA than allow that change to become law. The subsidy allocation changes appear to be a secondary political move. But despite the political posturing, there are genuine economic and political philosophies at odds here.