Hey everyone. I'm in the process of booking an international flight from Toronto to Rome. Like always, I'm trying to use Expedia. However, I've never booked an transatlantic fight before.

I found this one particular flight that takes off from Toronto Pearson (YYZ) in the late afternoon and lands in Rome Fiumicino (FCO) the next morning. First and foremost, this flight is listed as "United Airlines Flight 8590".

However, underneath "United Airlines Flight 8590" there is a note that reads "Flight 8590 operated by Air Canada".

If this note reads "Flight 8590 operated by Air Canada", which airline would I actually be getting on?

Would I actually be flying United or Air Canada?

Thanks everyone!