The cover for the airbox on this Honda generator hinges open to the left, but the frame rail is directly in front. The airbox is also bolted to the engine from inside (behind the filter).
I've throughly looked over this and there is no way to open that airbox unless you unbolt the engine from the frame, or perhaps modify the lid hinges with a saw so it doesn't have to swing as far to come off.
Looks like all 4 tabs release and you can pull it forward then out. Not sure if there is enough clearance though still. Doesn't look like it swings.
Clips on the right, half-hinges on the left. It swings open about ~110° before the whole lid can be removed from the rest of the airbox. It's a pretty common mechanism for airbox lids on small tools; Echo uses them a lot on trimmers and brush cutters.
That lid cannot be removed with the frame right there.