The initial public offering of 1 million common shares by Columbia Air, a new airline to be based at Baltimore/Washington International Airport, has been postponed until next week, according to E. F. Hutton, its lead underwriter.

The offering, originally slated for tomorrow, was put off following an amended filing to include new information that Scandinavia Airlines System intends to purchase 142,500 shares or 14.3 percent of the proposed new offering, according to Dow Jones News Service. Under the law, up to 25 percent of the stock of a U. S. airline may be owned by non-U. S. citizens.

According to others sources, the revised prospectus also includes new information that Air Florida has taken 9.9 percent equity in the new airline.

The prospectus also includes information on the allocation of landing rights for the new airline. If it was operating next month, the prospectus states, the Federal Aviation Administration would have allocated Columbia no less than 4 landing and takeoff opportunities--called slots--at New York's LaGuardia Airport, 5 to Boston and 3 to Pittsburgh.

It would also be able to operate four flights to Raleigh/Durham and four to Norfolk. The airline anticipates that similar slots would be awarded in January when it intends to start service.