OK, may be I should have said when approaching to an airfield and not attacking it. But let's use a little example. I made a little "statistic" based in a single experience, Frank Tinker's experience narrated in his vivid book "Some Still Live".
For those who never heared about him, he was one of the few American pilots that served as volunteer in the Republican Air Forces in SCW. In his memories book, written a year after fighting in Spain, he describes 18 enemy attacks. Most of them were over Campo X, and airfield so close to Madrid's front that was preferent objective of Nationalist bombers.
Of those 18 attacks, 13 are day attacks and 5 night attacks. In the night attacks, they always got the syren alarm, since they heared the roaring of Ju-52 approaching the field or they were telephoned from the front were noise had been heared. The only case of pilots taking off to face enemy in a night attack along SCW of which I read is the one over Sariñena airdrome described in other thread.
In the 13 attacks with daylight they always got an alarm signal of 2 red flares, since they were telephoned from the near front when troops saw the bombers approaching the field. In all the cases, they took off to face the bombers, shooting down sometimes some Ju-52 or making He-111 turn back to their lines.
The single case of surprise attack he narrates, made many run to the shelters, but not everybody. I put it here because It's worth it to read his own words. Actually it was a really small crazy attack, but...
The fighter he was using in this attack was I-16 type 5, in the attacks over Campo X, some months before, he flew I-15.
Yes, I know there are many other cases, as I said before, with the increasing speed of bombers, reaction to attack would become harder.
May be we need a double mod: pilots running to their planes, and running to the shelters. Then you could set their braveness/crazyness in FMB, the same way you do with ace, veteran, rookie pilot experience: You could choose between completely crazy, brave, prudent and WTF you damn coward...
Just jocking.