Cruise speed?
Max speed?
Airspeed?
Ground speed?
What speed, I need?

Most of the newer 737-700s have a max speed of 470ish kts. That’s about 540ish mph.
That’s the max speed the aircraft can fly (certified) through the air.
Their cruise speed is something like 450ish kts. That’s about 515-520ish mph.
That’s all standard day figures for the aircraft itself. No winds. Straight and level.

Now if they go up and catch a 100+ mph tail wind. Their cruising speed over the ground can easily break 590 mph. That number is not too fast.

The brochure is probably giving you the aircrafts max speed.
The commercial is probably giving you their average ground speed.
(At altitude)

Both are accurate numbers. Just a bit confusing when they don’t tell you exactly what speed they are talking about.

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1980 300D - Veggie Burner !