IndiGo's decision to ignore the call of Federation of Indian Airlines came hours after the government warned of "appropriate action" against those who disrupt the schedule.
"IndiGo appreciates the sentiments expressed by the Ministry of Civil Aviation that it understands the problems faced by the Indian aviation industry and that we should all engage in a dialogue with the ministry," IndiGo Airlines President Aditya Ghosh said in a statement.
Union Civil Aviation Minister Praful Patel, earlier in the day, said that the government cannot be expected to extend financial help to loss-making private carriers but he did offer to talk with them.
"The government reiterates its advice to private airlines against suspending operations on August 18," he said and warned that the Directorate General of Civil Aviation could "take appropriate action" to protect fliers' interest.
Official sources said if the airlines do not operate flights on a day, it would mean breaking the schedule and in turn the rules and procedures of airline operations.
Action could be taken by the DGCA on this count, they added. With IndiGo out, seven major private carriers under the aegis FIA may suspend flights on August 18 to protest high aviation turbine fuel prices and taxes on it, besides high airport charges.