Maybe I'm getting my versions mixed up but I'm fairlly sure I still have to turn on surface search radar after every dive. I've started a new career and don't have radar yet so I'm stretching my memory. I know I would actually look 'up' while on the bridge to check that the antenna was spinning and if not I would switch on.
Having said that, you are talking about aircraft traffic. The air search radar is definitely automatic regardless of version and comes on as soon as you surface and is sweeping 360. There is a mod which allows you to raise the air search antenna so you can check for air traffic while still submerged (I believe the modder utilized the unused snorkel effect for the US subs, regardless, it works). There is no 'manually setting' of this radar. There is no screen for that you will simply get a warning from your crew. If you are using time compression a lot then you will miss the warnings and come out of timewarp to find you are being attacked. This is excrutiatingly annoying if you are using stock 1.4 as there were waaaay too many aircraft popping up at ridiculous ranges while crossing the Pacific. Highly recommend you try TMO or RFB in conjunction with RSRD mods as the air traffic is much more realistic (and deadly).
