Flying from Sharjah to Bagram AFB today is an aircraft operating for "British Gulf International Company" as opposed to British Gulf International Airlines, using the ICAO code BGI rather than BGK. Why should this be interesting? Well, back in the beginning in 2003, BGIA was supposed to be a company from Sao Tome that had set up a subsidiary with Kyrgyz registration and transferred all but one of its aircraft there. Not that Sao Tome played any significant role in this - the offices, staff, and aircraft were in Sharjah throughout.
This blog later found out that the original Saotomense BGIA had never officially existed at all, not having been registered as a company. Neither had its aircraft ever been registered there before being transferred to the Kyrgyz registry (EX-) and beginning to fly into Iraq, Afghanistan, and Pakistan using the ICAO code BGK. Memorably, they got a DOD fuel card by the simple expedient of filling in the form.
But now, as well as the BGK-coded planes that continue to operate from Dubai and Sharjah to locations in Iraq and (more and more) Afghanistan, there are also BGI-codes out there.