Utilize the input text as a context reference, choose the right relationship between Heathrow hub and London from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

A clue to BA's lingering love affair with the 747 lies in the model's ability to eke out capacity from scarce operating slots at its London Heathrow hub at a time when lower fuel prices make retaining older planes an option.

Answer: headquarters_location