More accurately, you need 7.9 km/s to get into orbit. You can fly into space at a far lower speed of about 1.2 km/s; you just will fall back. That said; travell

More accurately, you need 7.9 km/s to get into orbit. You can fly into space at a far lower speed of about 1.2 km/s; you just will fall back. That said; travelling at 7 km/s at 12 km seems ludicrous; air is over 100 times denser at that altitude than at 25 km, where the Space Shuttle reentered the atmosphere (at about the same velocity). So this aircraft would need two orders of magnitude better heat protection than the Space Shuttle. Not to mention the aerodynamic drag at these altitudes and velocities, which will be tremendous.