Limited introductory fares of about $600 round trip are available.
JetBlue had set its introductory fares to and from five Florida cities at $69.
The airline plans to put about a third of its planes back in the sky over the next month, also with extremely low introductory fares.
Southwest said its introductory fares would be as low as $29 each way, if purchased 14 days in advance.
The introductory one-way fare has been $129 and is scheduled to rise to $149 next Wednesday.
JetBlue has announced introductory fares of $99 to $249 each way, depending on flight times and departure day.
JetBlue plans introductory fares of $79 each way, good for travel through Nov. 18.
JetBlue described the introductory fare as 40 percent lower than any in the New York area.
It runs every 90 minutes from 11 a.m. to 5 p.m. through summer; an introductory fare of $1 each way.
The airline says that flights during November are sold out as a result of an introductory fare of $999 round trip.