Allegiant Airlines typically releases its flight schedules and fares around six to nine months in advance, which means you can start looking for flights as early as that.
https://bookingtrolley.com/blogs/allegiant-airlines/how-far-in-advance-do-you-need-to-book-allegiant-airlines-flights
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733 3rd AVE FL 16 New York NY 10017 - New Alipore, WB 10017