An estimated 2 million workers are expected to protest changes in public-sector pensions with a 24-hour walkout.
The lines at Heathrow's immigration counters are expected to be so long that passengers will need to be held on planes, BAA cautioned.
"This in turn would quickly create gridlock at the airport, with no available aircraft parking stands, mass cancellations of departing aircraft and diversions outside the U.K. for arriving aircraft," Normand Boivin, the chief operating officer for Heathrow, warned in a letter to airlines.
COMMENT: The letter urged airlines to reduce the number of passengers they bring in on November 30. Boivin said the border agency expects to be functioning at less than 50 percent of normal productivity.
British Airways and Virgin Atlantic Airways have both agreed to waive fees for re-booking flights on November 30 and expressed concern over the strike's impact on business.
Government ministers have warned the nationwide could cost the economy half a billion pounds and lead to job losses. Heathrow Airport handles 180,000 passengers on a typical day, according to BAA.
Needless to say, travel through Heathrow in the days before and after the strike are also expected to be particularly heavy. Hence, air travelers who are routed through Heathrow may well want to call their carriers as soon as possible and see if a re-routing is possible or whether those engaged in optional travel can defer their departure date until conditions at Heathrow return to normal.