The cabinet is unlikely to consider a proposal to allow foreign airlines to invest in domestic carriers before the end of May, a cabinet minister, who asked not to be named, told reporters.

The ruling Congress party's biggest ally - Trinamool Congress - is opposing the proposal, the minister said, adding that the decision depended on the ally's consent as per a Reuters report.

Indian airlines, facing a debt-load of $20 billion and losses of $2.5 billion, have been hurt by high fuel costs and massive competition, and are looking for ways to bring in cash to run daily operations.

Under current rules, foreign airlines are barred from buying stakes in domestic carriers, although foreign investors are allowed to hold a cumulative 49 percent.