Was this common or not? Did the Poles use air recognition panels on their Shermans and Cromwells? Any photos?
In Bill Bellamy's new memoir: "Troop Leader: A Tank Commander's Story" he mentions using their "red air identification strip" which he laid across the front of his Cromwell "to warn the Typhoon pilots that we were friendly" just after 'Operation Goodwood' (pg. 80). He also mentions using 'yellow smoke' as I recall, in another situation in Normandy, with less effectiveness, as they were strafed anyway. Bellamy was a troop leader with the 8th Kings Royal Irish Hussars.
On pg. 89 in "The Black Bull" by P. Delaforce it mentions "the Fife and Forfar Shermans at Pavee" [France] using "orange phosphorescent panels displayed on the top" of their tanks to let American Thunderbolts know they were Allies along with "yellow smoke emitted by special smoke generators." This was on August 4, 1944 during 'Operation Bluecoat.' This effort did little good as they were bombed anyway.
Couldn't locate any photos but I'm inclined to think they would exist somewhere (didn't take the time to peruse the Concord bks. on British tanks in NW Europe, or maybe one of the old Osprey/Vanguards?). Perhaps someone with more knowledge than I could point you in the right direction!