It's Male Bovine Excrement.
It's a regulatory dispute, nothing more.
basically, the way UPS structured it's business vs how Fedex structured its business means one isunder the National Labor Relations act, and the other is under the RLA which covers railroads and airlines.
UPS feels that the looser regulations under NLRA give Fedex an unfair advantage. UPS wants Fedex to be covered under the same laws they are, and Fedex wants to keep their status.
Personally, I think they should both be covered either under the NRLA or the RLA, and they should figure out which they both want.
NRLA makes it easier to unionize site by site, while RLA requires it nationally. Personally, I think the RLA is more appropriate for both of them, but that's just me.