Ah, in the other thread I don't think you specified "with tow pkg."
The F150 tow package should have a 7-pin "blade" socket to the left of the receiver. Its pin-out is the modern standard 7-pin layout, and should work fine for you. *IF* the Airstream has never been connected to a modern vehicle, it may still have a non-standard pinout that you may need to adjust.
Here is a link to the standard pinout.
Note the "notch" in the trailer plug and the tab in the socket are the way to locate which pin is #1, and that #7 on the diagram is the center pin. If your trailer's connector is molded together and you can't swap the wires (and they're not already in the modern layout to match your truck) you can use an adapter or change the truck's layout, but changing the truck should be your last option since any modern trailer should use the layout your truck already has.