Which episode was it that Superman was disabled by loss of air?
It wasn't an episode so much as everytime that version of Superman was in space he was either in a spacesuit (Superman TAS episodes "The Prometheon", "Little Girl Lost, Part 1")
or in a Green Lantern energy bubble (Justice League episode "Savage Time").
Plus when the Zod expy guy and his female sidekick got spaced in their last appearance both after escaping the phatom zone and at the end of the episode they were shown gasping for air.(episode "Absolute Power")
So yeah I think its apparent that Superman needs air.
The Pre-Crisis Superman and Superboy were capable of space travel without the need a space suit. The 1986's reboot by John Byrne retooled the character to make him less powerful and more fallible. The 90's Superman cartoon was based on Byrne's reboot. Superman would regain A LOT of his powers and things Byrne stripped from the mythos after Byrne's departure in 1988. The ability to survive in space with the need to breath was returned in the 1999 comic prequel Our World At War. When Superman was trained by Mongul Jr to have better control of his powers and gain fighting ability for the upcoming war with Imperiex. The Superman of the 2000-2011 (I'm not too savvy on New 52 Superman) had nearly every ability of his Pre-Crisis self. Minus the unlimited power levels. He didn't need to sleep eat or breath as long as his solar cells were charged.
Bruce Timm's tooling of the character was really a product of time it was created. Similar to how Man Of Steel Supes doesn't have the same levels of power the Supes from Superman I-IV or SR. They were based on Pre-Crisis Supes who could travel through time in the comics and move planets out of their orbit under extreme duress. MoS Supes struggled to lift a falling oil rig structure.
Something that further explains why he could not possibly make the kinds of "rescues" some people felt he should have made in the second half of the film. On top of being inexperienced, he lacked that kind of power.