That was the time Mission Control said "What do you mean, Liftoff!"? There's an airliner up there!"
The captain spotted its launch immediately (perhaps he had advance notice) and drew our attention to it--said it was only the second he'd seen. He announced its progress for us: 10,000 feet, 100,000 feet, etc.
Being twilight, the rocket flame lit up the sky like a million Roman candles. To this day, it's one of the half-dozen most amazing and memorable sights I've ever seen.