A disgruntled consumer paid an undisclosed sum for a "sponsored tweet" to broadcast his frustration directly to British Airways' 302,000 Twitter followers.
The decision to highlight BA's customer service came following a trip his parents made from Chicago to Paris at the weekend, during which his father lost his luggage.
Syed tweeted: "Don't fly @BritishAirways. Their customer service is horrendous.”
Eight hours after the original posting and after the tweet had been picked up by news sites, the airline tweeted back saying: "Sorry for the delay in responding, our twitter feed is open 0900-1700 GMT." The carrier promised to look into the baggage issue.
A BA spokesman told NBC News: "We would like to apologise to the customer for the inconvenience caused. We have been in contact with the customer and the bag is due to be delivered today."
Shashank Nigam, chief executive of aviation consultancy SimpliFlying, said: "The implications are tremendous for the future of airline customer service, especially on social media.”
He told the BBC: "These tools are easy to use and brand detractors have the same access to them as corporations. I'd guess that this cost less than $1,000 to buy and Mr Syed targeted it smartly.”