Larry
The short answer is that quite a few airlines operate for on or behalf of DHL. There's EAT in Belgium operating 727, 757 and A300s. DHL Air in the UK operate 757s. Swiftair in Spain operates 727, Convair 580, Metro and Brasilia. SNAS in the Middle East operate Convairs and Metros. DHL Aero Expresso in PTY operate 727s and ATRs. There's an outfit in Africa operating Caravans, ATRs and very soon also 727s. DHL and Air Hong Kong are joint venturing with new built A300-600Fs to support the new HGK hub. Then there's the wet-leased, or sub-contracted part, such as Air Atlantic with Electra's and Gemini, Lufty and World with MD11s. And so on and so forth. Around 230 aircraft worldwide, give or take a few.