The first three are more like regular skips.
-before the second checkpoint i jump of to the right, hit the edge of the checkpoint, fly through a shelf and land the straight road
-directly after that I go straight, jump of straight, fly straight through a shelf nad land on the road straight before the road goes up and ends
-in the smelter room i also go very straight, I land a barrel roll at the edge of the furnace and then fly to the exit of the room.

The last two are truly build in shortcuts and the hardest ones i've build so far.
-in the welding room you can ignore the road by landing on the steel beams on the roof
-after that you can fly over the battlefield, getting cooldown by landing on the two planes. This shortcut is very hard to hit and you only got one changse. If you used the shortcut before you should not land on the ground again after leaving the steel beam.
While i am able to hit this shortcut with wing pumping i find it even more difficult than with thrusterboosting. With wingpumping there is absolutely no room for mistakes