Is a pilot physically seated in the aircraft in the QRA hangar, plugged into all systems for the duration of their `shift' with all essential avionics etc. powered up, ready to light the fire and get airborne - or is that only what happened during the Cold War?
There are some QRA videos online of Eurofighter Typhoons - but they seem a little unrealistic - pilots running to aircraft and strapping in - very WW2.
Very WW2? That's the way it was throughout the Cold War!!
Alert can held either mounted or dismounted. The number of minutes depending on the aircraft type, also the length of time that the state can be held.
Mounted states are aircraft and crew intensive and not practical for QRA. Unmounted alert times are generally driven by how it takes the aircraft systems to come on line, simpler aircraft requiring less, rather than pilot reaction time.
During exercises, whilst parked on the ORP, the Hawk could manage RS2 with the pilot in a deck chair beside the cockpit, though RS05 was the norm. For QRA the Lightning held RS10, which was achievable with the pilot in bed in the Q Shed. (I believe that for the RAFG Battle Flight they managed RS05, though I never served there so cannot confirm.
When the F4 took over that slipped to RS15, mainly, IIRC, because of the time required to align the INAS platform.
A certain tanker aircraft could hold RS30 for about a week. When asked what the limiting factor was I was advised they would hold it with the crew living down the back and they'd have to go off state once a week to empty the toilets and restock the rations........