1.   An official of the union that represents the controllers said such disruptions would probably occur again in coming weeks.

2.   Current FAA controllers are represented by the National Air Traffic Controllers Association.

3.   The union representing the controllers was not available for comment.

4.   Trades unions representing the controllers are protesting against a plan to change the state-controlled body for which they work into a joint-stock company.

5.   Unions representing controllers had called a four-hour national strike and this had attracted strong support from controllers, the authorities said.