Airborne equality

Next time an airline flight attendant lends a hand with your Gladstone bag, imagine great statesman William Ewart Gladstone in the next seat muttering his famous line, ''Justice delayed is justice denied.'' For only now, nine years after 3,500 women flight attendants won an equal-pay suit, have they been award-ed the back pay with interest that a federal judge believes they deserve. And payment is still uncertain as the defendant employer, Northwest Airlines, continues to appeal.

Appeal, of course, is a litigant's right, and the stewardesses have utilized it, too. But, even if the long process denies a degree of justice to either side , the case ought to have some deterrent effect on employment discrimination.

The judge's award of $52.5 million, the largest yet in such a case, fits with a national disposition not to accept gender-based unequal pay indefinitely. Complaints of unequal compensation - such as the stewardesses' claim that men with similar duties received $2,000 to $3,000 a year more - are far from a thing of the past. But even some of the staunchest opponents of the Equal Rights Amendment, for example, champion equal pay for equal work. And efforts are underway to define ''equal work'' fairly by recognizing the comparability of tasks beyond exact sameness.

Britain's Mr. Gladstone in the next seat might understand. After all, the United States has in a sense been following the kind of evolution that made the 19th-century career of this slave owner's son so striking - toward an awareness of the need for social and political reform and for the action to accomplish it.