This isn't just a standalone ad. It's part of a campaign. Anyone who walks 10 feet in NYC (or about 5 feet in Seattle) is going to have seen the same color scheme, typeface, and even sentence structure (brief, terse statements of fact asserting Delta's features). They will map this ad to what they've already seen.

One could also assert that the absence of a blatantly overt logo also triggers curiosity and leads the reader to more closely examine the ad ("Who has USB ports in every seat?"). I am pretty sure studies show that this sort of active observation or searching causes the message to better embed (as opposed to just a big logo which people gloss over).

I think most people who are in the market for long-haul international and who are riding Uber are probably going to recognize the DL symbol.