The planes would be delivered through 2027.
Models under the purchase agreement include Airbus A319, A320 and A321 models. Spirit Airlines' current fleet consists of all Airbus jets.
The deal, at list prices, is estimated to be worth between $11 billion and $12 billion.
The agreement announced Monday firms up a memorandum of understanding the companies reached in October.
The order would be subject to 10% tariffs imposed by the Trump administration on European airplanes.
The World Trade Organization in October said the United States could apply tariffs on $7.5 billion worth of European made goods after an earlier ruling that Airbus, a rival to Boeing (BA) - Get Report, had received unfair subsides from Brussels.