No dennis, look again...

The direction of travel is to the left, which meane the airflow will be from left to right.

In any case, Here are two suggestions. The first is the complicated, but cool way, and the second is the simple way

1 - Bombay style doors (Or a single door) that open sideways to the airstream.

2 - A single hinged "Trap Door" that will open when released by a pushrod that acts as a latch, and remains open throughout the rest of the flight