Well.. November 2003, so only after that can you claim "decades", plural.. it's a while yes, but clearly shows that at least it's in the realm of commercial aircraft, and may happen again, in principle.

Edit: By the way, that comment said, and I quote, "Name one plane that flies at more than 60,000 feet, I'll wait."

No word "commercial" there. So, aside from the Concorde, there were/are several others, some already mentioned.