If the unlimited data plan in the ThunderBolt announcement truly represents a "flavor" of tiered pricing as Shammo hinted, then perhaps Verizon will continue unlimited data plans for some time. But that seems unlikely given his other comments.

Shammo also told investors on March 1 that the unlimited $29.99 option would remain in place for the iPhone 4 and other 3G smartphones for the time being to avoid putting up a barrier to new customers, but he added, "that was never a long-term strategy."

Continuing unlimited data plans at any carrier seems unlikely, analysts have said, because of the explosion of data from video on smartphones, which is expected to worsen with LTE speeds and faster smartphones, many with dual cameras.

"Everyone knows unlimited data on wireless networks is unsustainable," said Jack Gold, an analyst at J. Gold Associates, reacting to Shammo's speech.

If the unlimited data plan for the ThunderBolt stays in place for a while, unlimited plans could also apply to three other LTE smartphones coming from Verizon: the LG Revolution, the Droid Bionic 4G and the Samsung 4G LTE.