Four airlines that recently adopted a trial "youth fare" plan have given up the project. However, two lines that operate out of Boston will continue the plan.

American and United Airlines offer passengers between the ages of 12 and 21 carriage at half the regular first-class charge and without jet surcharges. Students travel in coach seats; but, when the coach section is filled, first class seats are made available.

The originators of the idea, American Airlines, put it into effect last August 30 on a six month trial basis. American told the CRIMSON yesterday that there are not yet enough statistics available to estimate the success of the program, but they have received many inquiries and plan to continue it indefinitely.

National, Northwest, and Northeast Airlines will cancel the reduced fare on November 12. Eastern Airlines dropped the plan before it was to have gone into effect yesterday.

American explained that they hoped the youth fare would allow young people to travel who otherwise would not be able to afford it. The critics of the plan, of which Eastern is the most outspoken, feel that most of those who take advantage of the reduced rates have to travel anyway, and the airlines are giving up money unnecessarily.

There have already been many abuses of the plan. The age limit is difficult to enforce, particularly for women passengers, and students have bought tickets for their parents. Also, when groups of servicemen deal collectively with the airlines, it has been difficult to ascertain who is within the age limit and who exceeds it.