we had the X15 program which had it been continued and developed could have easily morphed into a successful space plane, but noooo -
Y'know .. there are the 4 uh... um .. cough.. um.. sorry 2 X-37B 's that are now under the jurisdiction of the Space Force and while more a small drone shuttle and not carrying personnel they have been doing important low orbit work since 2010 . One orbited for 780 continuous days another was launched just a few weeks ago on a SpaceX booster and is currently in orbit.
........
.