Regional airline Flybe would view a takeover swoop by Stobart Group as "opportunistic" if an official bid is made, the Press Association understands.
Flybe said it had not received an approach from the owner of London Southend Airport and advised its shareholders to take no action.
Shares in Flybe closed 36% higher on the London Stock Exchange after Stobart Group said it was weighing a potential approach for the Exeter-based business.
Stobart, which spans infrastructure, energy and aviation, is eyeing a tie-up as it searches out "alternative structures" for its airline and leasing business.
It said one option was to take a "non-controlling interest in a vehicle" to buy Flybe.
Updating the market, Stobart said: "Stobart Group and Flybe have a range of shared interests arising from Stobart Group's ownership of London Southend Airport and its aircraft leasing company and the growing franchise arrangements between the two groups' airlines.
"As previously disclosed in October 2017, we have been reviewing alternative structures for our airline and leasing business that can play an important part in the consolidation of the regional airline sector.
"A number of potential structures have been considered including taking a non-controlling interest in a vehicle to acquire 100% of Flybe likely to be in cash."
Flybe has been grappling with an IT overhaul and efforts to drive down costs, with half-year profits nearly halving at £8.4 million in November.
However, revenues climbed 8.5% to £158.8 million during the third quarter as passenger numbers rose 8.1% to 2.3 million.
In a statement, Flybe said: "Flybe confirms that it has not received any approach from Stobart Group regarding a possible offer by Stobart Group for Flybe.
"Flybe shareholders are strongly advised to take no action at this stage. There can be no certainty that any firm offer will be made nor as to the terms on which any firm offer might be made."
Shares in Stobart Group finished more than 2% higher on London's second tier market.