blueskybird,
I live in Ealing Broadway and commute everyday to LHR. Even though I don't work with an airline (yet), I am required to be there anytime between 0400 start to 0130 finish.
for the early starts and late finishes, my company provides me with free taxi but otherwise it is public transport.
Heathrow express gets you to Ealing Bdy from around 0500 to 2359 (roughly) otherwise the picadilly line gets you to Northfields and then the E2 bus gets you to EB -the whole journey takes roughly 30min-.
Last train from LHR is 0022 weekdays to Northfields and first one around 0510.
Hope this helps!