of fig1 in executing a three way swap in accordance with the invention and comprising part of the tertiary operations of fig4 are illustrated more particularly at logic step 110 of fig7 a the three way swap operation in accordance with the invention is entered the logic flow process then proceeds to logic step 111 to select from table iv a first of available subroute entries that were found to be feasible when swapped into the grounded aircraft route during the prior binary swap operations and to point to row one in table v from logic step 111 the logic flow process continues to logic step 112 to obtain and identify the starting and ending flights gh and gt of the grounded subroute entry selected at logic step 111 these flights are used to key into the table v grounded subroute entries that were found to be feasible when swapped into the available aircraft route during the prior binary operations the logic flow process then moves from logic step 112 to logic step 113 to issue a query to determine whether an entry in the available feasible swap table v corresponds to a key using the starting and ending flights of the grounded subroute gh and gt that were selected in logic step 112 if a match is not found the logic flow process proceeds from logic step 113 to logic step 116 to determine if there are more entries.