Infratil says it would consider investing in its two British airports to change their functions to help make them more attractive to sell.
The listed infrastructure investor's Glasgow Prestwick and Kent airports are for sale after years of underperformance.
Last week, Dutch national carrier KLM confirmed it would start making twice daily flights from the Kent airport to Amsterdam from April 2013.
Infratil executive Tim Brown says the process of selling the airports has taken longer than the company expected.
He says the company now has to look at a range of complex proposals and if the use of an airport is going to change, it will have ramifications for local communities.
Mr Brown says if airports are very successful then councils or cities often then tax them, but if they are struggling they may then either need subsidies or be closed and put to alternative use.
He says the debate then becomes more complicated, which makes timeframes more difficult to guess.
Mr Brown would neither confirm or deny whether Infratil is looking to buy Stanstead Airport in London.
