Steve.
The photos you refer to have not disappeared, they were deleted.
In many cases these were images taken during your 2011 Aviation Tour of progressive series of aircraft landing or taking off and those deleted were considered to be very similar to others uploaded. Further deletions may result, for example 755420 with 755419 and also 755445 with 755443.
The last posting on the Member Message Board stated the situation in respect of such images very clearly.
Please try to avoid doing so in the future.
Our site welcomes all images in the ownership of the uploader without any screening with the exception of the the above and we look forward to a continuation of your valued contributions.
Malcolm.
Admin Team.