American Telephone & Telegraph Co. introduced yesterday a nationwide, one-stop calling service for business travelers that offers three-way calling, voice mail, language interpretation and other features.

To use TeleTravel, subscribers dial a single "800" number to gain access to half a dozen services designed for business travelers. Once inside the TeleTravel system, subscribers can move from one service to another without having to hang up and call back.

The service carries a basic subscription fee of $10 a year. Nearly everything except basic calling carries an additional fee. Surcharges can run as high as $2.75 a minute for language interpretation.

Once connected to TeleTravel, subscribers can place local, long distance and international calls. TeleTravel rates are comparable AT&T;'s regular daytime rates, the company's highest.

TeleTravel also offers:

* Three-way and speed calling at no extra charge.

* Language interpretation at $2.75 a minute for more than 140 languages.

bTC * Up-to-the-minute airline flight status information for 75 cents a minute for major U.S. airports

* A message service that allows subscribers to pre-record messages up to a week in advance for delivery anywhere in the world. Domestic messages cost $1.75 each. The fee for international messages varies.

* Voice mail for 39 cents a minute plus $15 a month per mailbox.