But it was what happened late in the afternoon that underlined the grave risk to the government of losing ground in what is Syria's largest city and its economic capital.

First came an unmistakeable sound that has so far been absent in this conflict - the roar of fighter jets.

What appeared to be Russian-made MiG planes arced through the sky. We watched as they dropped in, bombing and strafing rebel positions.

I've been taking a look at the various video of fixed winged aircraft spotted above Aleppo following this report by Ian Pannell of the BBCA number of videos supposedly from Aleppo showing aircraft flying through the sky, for example this one from Bambuser and this one from Youtube , and are generally pretty unclear, so making out the shape of the aircraft is difficult. However, one video has been posted that has a great shot of the aircraftI've blown up this screengrab to get a clear idea of the silhouette of the aircraftLet's compare that to some of the aircraft listed as being used by the Syrian Air Force, first the various MiGsThe above two aircraft are a MiG-21 and MiG-29, both of which clear have wings that look nothing like the aircraft in the videos. Then we have MiG-23 and Su-24, with variable geometry wingsTo me it looks like the wings are too thin, and set too far back, plus it appears in the video there's something on the end of the wings, and what I believe we are seeing in the video is an Aero L-39 Albatros Here's a clearer top down view which we can compare to the still from the video