What is the correct pronunciation of Etienne Aigner?

I'd say close to "A T N" "Ehn-yay" - anyone else?

Yep, I was logging in to say pretty much the same: A T N N-YAY. This assumes Mr. Aigner isn't 3rd generation American and has Anglicized, of course. In that case, the typical butchering (Agner) would be more correct than I've ever given it credit for being...

ATN is a bit too hard being from Quebec we would sat eh teh nnnn not so much aay as ey or eh at the beginning and the t should be weak In quebec for anglophone (english speaking) to get the good pronunciation we rhyme with english words so here goes

eh like beg

tieh like tia maria

nnn like nnunn

The nnn should be long indicating feminine

It's difficult to know what some of these suggestions mean (ATN may be clear for the TN if that means pronounced like letters of the English alphabet but the A could be pronounced as ah or ay, neither of which is what I would say or think is correct as I don't think there is any accent mark on the e). I agree with oneillchris on that one. Etienne is a French surname.

Interestingly, I just read an online oral history from his brother who said Etienne wasn't his real first name as the family was from Hungary. He adopted that surname in Paris (the equivalent of his real Hunarian surname), so it is French. I think the last name is not French, but is actually German or Austrian. I don't know how his family pronounced it, though, he didn't say in the transcribed interview.

Etienne Aigner did move to the US after moving from Hungary to Paris

Etienne is the French for Stephen (if his name was originally Hungarian, it would have been Istvan). I would pronounce it something like Ett-yen, though you'd need to spread your mouth a bit wider with the lips closer together than that would suggest.

As for Aigner, aggiemom is right for a French pronunciation if they take it as a French name. If they think it a German name, the French would pronounce it Egg-nair, and a German speaker would pronounce it Eye-gner. I'm not sure whether the Hungarians would pronounce it any differently from the Germans (maybe Eye-g-nair?), so take your pick.