Airlines including Air India, IndiGo, and SpiceJet have issued travel advisories warning of potential flight delays, diversions, and cancellations across northern and eastern India due to dense fog and poor visibility. Major airports like Delhi and Kolkata are particularly affected. Airlines are advising passengers to check flight statuses and offering rescheduling or refund options under their 'FogCare' initiatives to mitigate disruptions caused by the adverse weather conditions.