OK, here's a totally nuts, half-baked idea, so it should fit in perfectly on these boards :-)
What if the PBY were indeed flyable, but it also flew as a bots? The bots would do two things: reveal enemy location in a sector (like dar), and automatically land to rescue downed flyers.
The bot PBYs can be shot down, which causes loss of enemy location (like taking out dar). People would fly cover for the bot PBYs.
Mutha