If I were you, I wouldn't keep the flight suit on in the house. As the reply above says, it just isn't fair. Poop all over things is something that you unfortunately sign up for when you buy a bird. I would definitely try to get him potty trained as soon as possible. It really isn't something you can rush though. It takes time and patience (as do most things when it comes to birds). For now, all I can recommend would be investing in a large play-stand (size appropriate for his tiny feet of course..) Or do what many people do, make one out of PVC pipes! This way you can place paper towel or newspaper underneath and avoid the poop on the floor while your doing household work. PVC pipes are generally pretty inexpensive and you can customize the play stand to your birds needs. You can look some of them up either on you tube or google images and get some inspo. For a tiel if you were to make one I'd get 1/2 inch pipes. My tiel and budgies love their stand and I have been able to change it around several times without having to purchase new tubing or make any new cuts in the pipes.
Also just a tip, if you were to make one out of the PVC piping the birds can grasp onto the pipes very well so your required to wrap it with some sort of grip, especially for medium/ small birds. I used a horse bandage wrap. It comes it many different colors and patterns and they are safe and non-toxic for birds.