I am not trying to down-play anyone's experience, but as this is such a rare item/subject, I think there are very few if any people out there who have had experience handling a real uniform of this type, or indeed any other items pertaining to this period of aviation history in Russia.
Unfortunately, I am going to have to concur with the earlier poster who casted some doubts on this item.
No, I do not have the photos or the auction number (the seller keeps all listings "private"), and for all I know this could have been acquired directly (not via Ebay) from the seller or from someone else who bought it from the seller, but this was one of the pieces Tsars Arsenal had, or on one of the other IDs he uses (he has several, but it is always easy to tell since the photos and description style are basically the same).
I remember seeing it listed several times over the course of 1-3 years ago, and took notice.
The asking price was something like $1,500 or $1,800.
The truth is, unfortunately, this seller is a faker. Several tell-tale signs exist in his fakes, one of them being the way dirt/dust/staining is always applied in the same fashion on all his wool uniform items. This is the most apparent in his photographs, but upon closer inspection the metal pieces are also artificial weathered/aged. I have seen some of his items in person, and can attest to this. He is also well known as a faker of Russian icons and religious antiques, but that is a different subject not for this forum.
But aside from this, there are some other simple red flag elements.
This seller always (and I mean "always") has exceedingly rare items which are textbook examples. Indeed, many of his auctions actually have had uniforms that are essentially modeled directly after a drawing in a book with the matching equipment that is shown in that drawing. Much of his uniform sets are supposed to be Russian Civil War items, and as anyone who studies this period knows these drawings in uniform history books are just composite examples, as each soldier/officer pretty much would have had varied looking uniforms and equipment, and the chances that a real uniform set would be found that matches one of these drawings in a book precisely is literally very low. Yet, this seems to be a common theme in his items.
But, also, they are always under priced. For example, he routinely (on his different Ebay IDs) lists White Army Kornilov Division uniforms as original, and absurdly lists them at, again, $1,500 or $1,800. However, any real uniform of this type (of which are virtually non-existent) would easily be in the thousands and many people would bid on it, and the seller knows this. Why does he do it? Because he knows that collectors who are really knowledgeable and have such funds to invest would never touch it as it's an obvious fake, but a more hopeful and novice collector would see it at this price, and think it was a deal.
The pilot's uniform shown in this thread is the same uniform as this seller had. If not, then there are two of the exact same uniforms floating around with the same insignia placement, cap, and badge set.
I am sure whoever purchased this is knowledgeable and not a novice collector, but items of this genre are just so rare (and possibly even non-existent) that we are all novices when it comes to this. However, that it came from this seller, unfortunately, causes real doubt to its authenticity to the point of certainty.