Jag tror att du söker boken "Black and Blue Magic". I boken är det inte hans farbror som ger honom flaskan med den magiska salvan som växer vingar, men en skyddsängel som försöker nå sitt eget mål för att hjälpa hans laddning.
Även om du angav att den inte hade någon bild, är omslaget listat nedan med en kort beskrivning.
Black and Blue Magic på Amazon
You'd think that someone with a name like Harry Houdini Marco would be deft and skillful, but Harry could only occasionally catch even an easy fly ball without making some dumb error. On top of that, most of his friends' families were moving to the suburbs. It would have been a long, dreary summer, but then a Mr. Mazeeck showed up and turned out to be more than he seemed. After helping the elderly gentleman, he receives a mysterious bottle with something very special inside as a reward and with careful instructions as to how to use it. The gift of flight.