Parallel Air is a Super Mario Bros. 1 ROM hack that differs from the easier Air and the harder Air 2, all hacks of which are created by U1.
Parallel Air is easier than Air 2 because it still retains its midair jump cheat. It also has 3 levels, each with separate rooms, which are remixes of levels from the original Air. Besides the fact that Parallel Air doesn't mark where the hidden blocks are, it is harder than the original Air because some of the rooms have changed their designs to be more difficult.
This is an unexpected improvement of almost three seconds over my original 2018 run, mostly thanks to a new strategy involving avoiding the Super Mushroom in Air 1-1!
Download the IPS patch here.