There is so much damage to the paper that I can think of no way to "repair" it, especially since the handwriting is in the damaged area. Also, it appears that there may be some damage to the stamp in the upper right and perhaps some of the perforations?
With all respect to these interesting posts. Sometimes a cover that is not an official first day cover has interest and value, if only personal. I have kept a few envelopes that come my way, not but a few. I have rules, all handprint or hand writing, and a good clear postmark and something interesting about it. They matter to me. Women's sports do not get the same coverage and ballyhoo, esp. not back then and not now. I want to look up this woman aviator. Maybe she did the best she could to memorialize the event. I see that these are somewhat older posts but; I am so glad that I found them. Thank you.