Things I don't see anymore?

I see one advertised in this months Trailer Life.

By "plastic nose covers," do you mean bug screens?



They were very popular in the late 80's early 90's time period, now a lot less so. I used to have one. They also helped prevent dings to the front of the hood by thrown pebbles.

As for the toppers, as others have said, they are quite common. I have had them on my 2 fifth wheels. They are especially useful for drenching someone standing in the wrong place when you bring in the slides after a rain and they suddenly dump all the water they have collected. :)

As stated, the "air foils" for pickups never mounted close enough to the front of the fifth wheel to be effective (look how close they are to the front of the trailer on modern tractor-trailers). In addition, the aerodynamic design of the front caps on most new fifth wheels does a far better job than either a bolt-on air foil or the older squared-off front ends of fifth wheel RVs. Finally, the best thing you can do for mileage while towing is to slow down.

Rob

Ditto above.
Air Foils/Wings can work, but you just about need a large Air Chamber to view the air flow and adjust accordingly.
As for Slide toppers, where have you been camping, they are all over the place, probably at least 50% of RVs have them, while they are a personal preference.

The air diverters never mounted close enough to the trailer to be very effective. They did move the bug splatter pattern, but from my reading, had no effect on mileage.
I've had slide toppers on my fifths and mhs for a long time. I rate them very highly.

Do you mean something like this? (not mine).

Air foils ??

Nose covers ??
Can you be more specific