The November 30 UK Border Agency (UKBA) strikes are a "serious kick in the teeth", says airline Virgin Atlantic.
"Virgin Atlantic is very concerned about the effect of Wednesday's public sector strikes on passengers and airport operations," said a spokesperson for the UK's second largest longhaul airline.
"This is another serious kick in the teeth for UK plc - Britain cannot afford to be closed for business."
To minimise the number of passengers coming through UK airports on November 30th, Virgin says it is encouraging its inbound passengers on that to "re-book for travel up to four days earlier or later".
"Along with airport operators, wider aviation industry and other airlines, we are in continued discussions with government and UKBA about possible contingencies," they added.
UKBA staff are walking out as part of wider public sector strikes against the government's proposed pension reforms.
This leaves border controls understaffed, with the government saying military personnel may be drafted in to make up the numbers at passport control.
Airports up and down the country will be affected. Inbound passengers are being urged to have all their travel documents ready, to make the passport checks as quick as possible.
"We are concerned that the UKBA strike on November 30th creates considerable uncertainty for our customers booked to fly into UK airports on that day," said a spokesperson for British Airways (BA), the UK's biggest airline.
"We understand that there will be a significant risk of severe delays in passing through passport control, with potential knock-on effects on wider airport operations.
"We are doing everything that we can to protect our customers and continue to liaise closely with Government, UKBA and airport authorities about possible contingencies."
BA is offering free rebooking of flights from November 30 to a different date.
British Midland International (BMI) is also offering free re-booking of flights.
"BMI plans to operate as normal during this period and is doing everything possible to minimise any disruption," they said.
A spokesperson for the Public and Commercial Services union (PCS), which represents 14,000 UKBA staff, said they have no choice but to strike.
"None of the public servants we represent want to strike, but they are being forced into it by a government determined to raid their pensions to pay off a deficit caused by greed and recklessness in the financial sector, and by cuts to their pay and jobs," he said.
"Instead of scratching round trying to cover the borders with under-trained staff without the proper security clearance, ministers should talk to us about the key issues affecting millions of public sector workers."