Million years ago ..... VC-10 ex-London overflew Boston en route New York, and on approaching JFK was given a holding time that would have meant landing with less then the minimum required on arrival, and certainly less then required to divert to any suitable alternate, so immediately diverted back to Boston, where ...... the WX had deteriorated due snow, and was way below any possible landing minima. Now no diversion fuel left - what to do ? Emergency landing at a USAF base was approved, and succeeded. Phew ! (Nb, not me )