Uncle Jack browsed though the aisles until he found one particular set of outfit. He took it into the other changing booths and after a few minutes of audible struggling he emerged from it. He wore a black hoodie, a black backpack and fairly baggy pants, or at least they would be if they weren't a couple of sizes to small for him. On his feet he wore a pair of black inline skates. He struggled walking with them as he approached you before putting on the final piece of the costume, a full face rubber gas mask. He put on his hood and took in a deep breath.
A wave of changes emitted from the mask changing both the clothes and Jack. Jack seemed to shrink quite a bit and his clothes started to look different. The typical structure of the fabric seemed to be gone and it appears to have lost its natural shininess gaining an extremely matte finish. Jack now fit his clothes and moved way more agile, circling you on his skates. Somehow he seemed a bit out of place, like a... "Paining?" he replied in anticipation. "Well come with me and I'll show you a place where we can try you out", he said while skating into a closet.
The closet itself was very small so you had to stand outside to see what Jack was doing. He got some spray cans out of his backpack and started to spray them on an empty wall. He painted a scenery showing a runway and some hangars, a small airport somewhere on a green plane. More and more details came to be as Jack spray painted them. "I didn't know you were that good with the spray can.", you ask. He replied, "All part of the costume.", before finishing and grabbing your arm, pulling you with him into the painting.
The world around you looked like it was painted, perhaps not unlike a cartoon. Looking back you see what would be best described as a hole in the world, enabling you to look back to the closet. Jack circles you on his skates, "So how do you like it?". You scratch your head and look around. "Yeah... I think this will do" and sit down on the runway and change your feet into wheels. As you watch the tires pushing through the soles of your boots you notice that 2 wheels are to little and wonder where the 3rd one would be. Instinctively you triggered the change and felt some pressure in your crotch area. Jack politely turned the other way skating in front of some of the hangars. Curiously you try to feel the ever growing tire and eventually it starts to move freely connected to you via some sort of rod. This excited you, but reaching into your pants you notice that your member must have become part of it. As you concentrate on more changes, your legs in front of you start to merge into your growing torso. Your arms, which you stretch to the sides become longer wider and flatter as they change into wings. Your nose pushes forward even more as your neck grows forming an aerodynamically sleek form from the tip of your nose to your body. A canopy forms on your back, becoming transparent, and your tail finishes the form as it turned into the tail of a plane. After what were only minutes you looked like a complete plane.
Jack skates back to you and hoppsonto your wing opening your canopy and climbing into your cockpit buckling up. He closes the canopy again and said "Ready when you are" while patting the top of the instrument cluster in front of him.
You start your engine which spins up your propeller pulling you forward against your brakes. As you release them you give its pull and gradually accelerate towards the runway feeling their wind on your surface. Instinctively you feel when you have reached take-off speed and pull up gaining more and more height way before the runway ends.