How many Pilots are on the DHL payroll in Europe?? Not contractors, people who's paychecks actually carry the DHL logo and employed by DHL.
Can a US airline outright own and control an European airline??
You do know that there are Fifth Freedom rights between Europe and US??
Thats how FedEx and UPS work in Europe (at least pretty sure). There is no law that would prevent an European Cargo (or pax) from doing the same. Except the law of economics.