10 MW was a theoretical number, all actual TGVs (unless you count the Eurostar as TGV) are a bit less. 400 passengers per modern European high-speed train (standardised 200 m length) could be considered a norm. The newer of the normal TGV derivatives (with their traction heads at both ends taking up place) have 377 seats, the double-deck TGV Duplex has 512.

Average speed depends on the distance travelled, and slow sections (for example connecting line into a major city) encountered. The TGV currently holds the start-to-stop average speed record (some Lyon--Aix-en-Provence schedules) at 263.3 km/h, but a typical average speed between high-speed line stations in Europe would be still somewhat under 200 km/h.

For an airliner, I don't know what's typical, but taking comparable capacity, let's look at an Airbus A340-600: 380-419 seats, and four engines of 249-267 kN maximum thrust each. Assuming a rule-of-the-thumb cruise speed of 900 km/h=250 m/s with a quarter of maximum thrust, I get around 65 MW.

Average speed remains, but I don't know much statistical data about that, I guess you have to ask frequent-flier Jérôme or rely on your experinece (sorry  I flew only three times in my life). For the comparison to make sense, you would have to include not just ascent and descent, but time on the taxiway and the check-in, maybe even travel from the city centre (though if you arrive with train in the city centre, often you have to travel too, so the difference is again not clear). But just from the stomach, an example: Frankfurt/M-Paris, an air distance of about 450 km, the time between departure and arrival (is that the time between boarding and exiting the plane?) is 1h10m-1h20m, let's assume 40-50m for check-in resp. check-out, and 30m extra for travel into the cities at both ends, gives an average of about 180 km/h.

BTW, just found this image of an A380 formation flight on the Airbus site:

_{*Lunatic*, n.
One whose delusions are out of fashion.}