This story is one that touches everyones heart and I know we would all like to see Potter Pooh reuinted with his loving family. Just jumping in here with what is likely a more plausible solution for you. Our pilots are fantastic, and will often go beyond measure to help out with situations like this. The problem becomes the long distance you need. Most pilots are willing to fly 250 nautical miles one direction (roughly 300 static or ground miles so you can compare). The distance you are asking for is over 2,000 miles. It will require several, likely 6-7 pilot volunteers, temporary overnight fosters as this cannot be accomplished in one day. Another huge factor is the weather concerns and mountain flying. These present limitations for many pilots which means even if they would like to volunteer they may not be able to fly in certain conditions. So here are two other suggestions for you.
One if to start a chipin.com site with your story and photos. People do this to raise money for special needs. You can then use those donations to have Potter properly vetted with certificates he will need to fly, health certificate and proof of vaccine, purchase him an airline approved crate, and send him on a commercial flight from Texas to WA. It will be faster for him and there is a wonderful article on our homepage, pilotsnpaws.org under Resources that says Commercial Transport. It was written by one of our volunteer pilots who is an airline captain. She shares with you how to best go about making sure your pet is taken care of on a commercial flight. Continental/United does a great job.
Second option would be to contact Operation Roger. They are long distance truck drivers who will often help families and rescue animals like yours.
It is outstanding to see the pilots who have volunteered so far but there is much more to coordinating a distance this far. It is not easy and though I realize you are not intimidated and willing to learn what you need to do to help get Potter home, you need guidance if this is going to work via Pilots N Paws. It's simply just too far with so many opportunities for this to go awry.
Please consider these other options in case things do not come together as you need them to. Rooting for all of you to be together again!