You are right that they are benefiting from the problems at Jet. They are not only getting Jet’s carriers and landing rights but also their market share. The problems in Indigo cropped recently between the two principal promoters of Interglobe Aviation (owner of Indigo brand). Co founders Rahul Bhatia and Rakesh Gangwal have equal ownership in the airline but Rahul Bhatia holds a much a more coveted position in the form of right appoint key managerial personnel, right to nominate 3 independent directors etc. Rakesh Gangwal only has the right to nominate 1 independent director on the board of Indigo. The Shareholder Agreement expires later this year and Gangwal wants to prevail upon Rahul Bhatia to have a more equitable sharing of powers in running the company. That is one of the major reasons why the tiff is out in the open.

Most analysts do mention in private that there are other reasons too for the promoter tiff. For example, if either party wants to sell the stake, it can quite complicated as they will have to give the other party right of first refusal. That is the reason; both the promoters have appointed legal advisors to help them iron out the differences. You may have to wait till October when the shareholder agreement expires but this is normally an overhang for any stock, when two promoter groups are not on best terms.