Kayak’s chief marketing officer Robert Birge told Wired.com:
"We have contacted them through official channels about concerns about the similarities between Bing and Kayak. From the look and feel of their travel product, they seem to agree with our approach to the market."
Microsoft confirmed that Kayak had been in touch, and said to The Register:
"We are discussing the matter with Kayak. Bing Travel is based on independent development by Microsoft and Farecast.com, which Microsoft acquired in 2008. Any contrary allegations are without merit."