they say a plane is efficient compared to a car but forget that cars and planes don't use the same fuel so it's bullshit, but I'm hoping their numbers are right
The numbers you give for the 747 don't look unreasonable to me, but it seems worth noting that jet airplane efficiency is downright awful compared to other mass-transit. While jet planes are the only practical solution in many cases (overseas, extremely long haul), they're overused in the U.S., where poorly developed regional transit leads to an over-reliance on inefficient (in terms of fuel usage, landling slots, etc) regional jets. It would be a good idea to better develop regional and medium-distance rail, and concentrate on using air-travel for cases where it works better (many countries have already done this of course).
5 gallons of jet fuel per mile is around 450MJ/km; if we assume a 747 holds 450 seats, that's about 1MJ/seat-km. A bit of googling suggests that this is roughly accurate, but probably based on cruising efficiency only; takeoff/landing is much less efficient, and regional jets are signficantly less efficient than large ones.
Modern HSR (and modern non-HSR electric rail) uses around 0.15MJ/seat-km or better....