I wouldn't be so quick to discount the possibility of bombers relocating in emergencies, then flying mission quickly. I believe I am correct in saying that the ground echelons of the air units are represented in an abstract fashion by "air support" units in the land units.
Here is a summary of US 5th AAF activity from Dec 17-22, 1941:
Wednesday 17 December 1941
B-17's, evacuating Luzon, begin arriving at Batchelor Field near Darwin, Northern Territory, Australia. Captain Floyd J Pell arrives in Australia to begin arrangements for the use of Australian facilities by the Far East Air Force.
Friday 19 December 1941
The air echelon of the 93d Bombardment Squadron (Heavy), 19th Bombardment Group (Heavy) transfers from Clark Field, Luzon to Batchelor Field near Darwin, Northern Territory, Australia with B-17's. The ground echelon is attached to the 5th Interceptor Command (Provisional) and will fight as infantry on Luzon and Mindanao Islands in the Philippines.
Saturday 20 December 1941
The air echelon of the 30th Bombardment Squadron (Heavy), 19th Bombardment Group (Heavy), transfers from Clark Field, Luzon to Batchelor Field near Darwin, Northern Territory, Australia with B-17's. The ground echelon is reassigned to the 5th Interceptor Command (Provisional) and will fight as infantry in the Philippines.
Monday 22 December 1941
9 B-17's from Batchelor Field near Darwin, Northern Territory, Australia, attack shipping in Davao Bay, Mindanao Island and land at Del Monte on Mindanao Island. HQ 7th Bombardment Group (Heavy) and the ground echelon of it's 9th, 11th and 22d Bombardment Squadrons (Heavy) and attached 88th Reconnaissance Squadron (Heavy) arrive at Brisbane, Australia from the US. The air echelons of the 9th and 11th are enroute from the US to Australia with B-17's; the air echelons of the 22d and 88th are operating from Hickam Field, Oahu, Territory of Hawaii until 5 January 1942 and 10 February 1942 respectively with B-17's. The 16th, 17th and 91st Bombardment Squadrons (Light), 27th Bombardment Group (Light) transfer from Ft William McKinley to Lipa Airfield, San Fernando and San Marceleno, Luzon respectively without aircraft.
Note that moderate-sized B-17 raids are launched from Darwin using planes emergently evacuated from the PI within 5 days of a US officer being flown in to coordinate with the Australians. Some of the planes were being ferried to Darwin
2 days before the raid. Note also that ground echelon components of air groups were arriving in Brisbane all the way from the US within
2 weeks of the start of the war [X(] The fighter groups were also being ferried about with alacrity.
I would say the game does a very good job of modeling the evacuation of US air groups from the PI. I doubt the game mission planning routine would get off a raid bigger than 9 planes from Darwin if you sent 3 or 4 beat up B-17 groups down there in 2 days without suficient ground support or an air HQ.
BTW...here is the link to the chronology of the 5th AAF month by month (very interesting..especially the sections on the use of B-17's for solo naval recon and attack)
http://www.kensmen.com/