[fsbofk]

I believe many, if not most, Allied fighters included cockpit heating. Among this group, the P-38 Lightning's heating was notoriously poor, such that pilots on long escort missions in the ETO suffered from the effects of the cold. Warren Bodie's The Lockheed P-38 Lightning includes a list entitled "15 Bad Points of the Lockheed P-38" - the fourth item "Insufficient cockpit heat" follows three of the P-38's major problems concerning the engines, wing intercooler, and compressibility.