Unite union leaders are meeting their counterparts in the United States today to discuss the planned walkout by cabin crew.
Teamsters, the main transport union in the US, has said it will support the union’s decision to strike.
A Teamsters spokesman said: “We stand in solidarity with our brothers and sisters at Unite who are fighting for a fair contract at British Airways.
“The Teamsters are an active member of the International Transport Workers Federation. ITF affiliates around the world are mobilizing to support British Airways workers in their fight for passenger safety and worker respect.
“Teamsters General President James P. Hoffa has been in communication with Unite’s Joint-General Secretary Tony Woodley regarding his members’ struggles with British Airways management.”
The airline said it was “sad to see Unite seeking backing from trade unions overseas”.
BA cabin crew are to strike for three days from March 20 and four days from March 23 over pay and working conditions.
All flights from London City and two thirds of services from Gatwick will continue to run, with Heathrow being the hardest hit.