Timed from skipping cutscene to first fully black frame.

There's an annoying softlock on this level where going too fast through the plane graveyard makes 1-3 of your teammates despawn which softlocks the level a bit later on. To avoid this you should wait until all your teammates are near the mortar pit before you cross a checkpoint midway through the section. Your teammates seem to vary here a bit, sometimes being slower and sometimes faster so you need to look behind you to see where they are.

The airstrike strat at the end is the fastest way you can do that section. Explanation is in the video description.