I highly doubt that these 319s will be going from Spirit to Tiger. I think that if Indigo could get its hands on more aircraft for NK they would be all over them right now. The last thing they would want to do is continue to shrink NK.
Tiger has leased 2 A320's to a company called SeAir out of the Philippines that hasn't started flying yet. These 319's could be replacing them.
And just for a correction Indigo limited Ltd. did not take delivery of those aircraft you see on the spreadsheet. There is an airline in India that flies New A320's called IndiGo.
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