I used Redtail Aviation
last year and had no problems. Our two shuttle drivers drove to Dirty Devil, camped the night, drove one vehicle to the airport and were picked ~8am. The rest of us at Potash just floated down the two miles and met up with the shuttle. Everything was on time and would do it again!
This is what they said in an email:
I have a perfect solution for you! We can fly your drivers from Hite up to Caveman Ranch which is only about 2 miles south of the Potash put in so if your group can meet your drivers there we can fly them right to the river!
We can do shuttles any time on any day that you might need and we can fly as many people as you need as well. The per person cost for that shuttle is $140 and we only have a 2 person minimum so it sounds like your group would be good to go!