The meta search site believes its US strategy to offer two different user experiences based on the same search platform could work as well in the UK.
Kayak bought Sidestep last November for $175 million and has continued to run the two brands in the US side by side.
The possibility an about-turn comes after traffic to Sidestep UK was re-directed into Kayak within weeks of the acquisition.
Chief executive Steve Hafner said: “In the US, Sidestep has a different look and feel than Kayak. We would support both brands in our search engine marketing buys and there are efficiencies to doing so.
“For the same keyword, each site could have a different bidding strategy and occupy different positions on the search result page such as #1 and #5. ”
There is no fixed timescale for reintroducing Sidestep but during the Travolution conference in April, Hafner said: “We retired the brand here because it had not got the traction.”