I was just thinking...

How many miles do the airlines give out in one day or on one flight??

Is that flight JFK-DCA, or LAX-LHR?

In a recent flight I thought I heard the FA say "a welcome to the 70 Mileage Plus members on board" (plane was completely full, seats about 120-130).

but on that UA flight were probably in add some: DL-ff, LH-ff, etc, etc.

then I would like to know:
* how many of those miles are (by the airlines fault) never credited correctly?
* how many miles are only credited after claiming them extra later?
* how many miles are used each day/per flight for awards?
* how many miles are wasted and never cashed in?
* etc. etc. etc.

Good questions Rudi (I doubt if anyone knows the answers to all these questions).

q1 - In my experience airlines are usually much better in crediting than their partners. I would estimate that with United, the number for me is smaller than 5% (probably around 2%), and I think that most if not all of those cases involved some change in schedule. Since I fly United only, and not the partners, this number is very low for me. This year I have flown 40 segments with United, all of them properly credited.

q2 - depends on how often people followup to see if the miles have been posted or not. In my case I will followup if the miles have not been posted, and I have never failed to get the miles in such cases.

q3 - some of this information is published, e.g. by Consumer Reports, although still not exactly.

q4 - some of this information is published. e.g. by InsideFlyer, where they report how many miles expired.