Hawaii, Alaska and Puerto Rico were in discussion for statehood at many points -not always overlapping- before it was made a reality for all but the latter. Alaska and Hawaii were thrown in together to address their opponents' concerns: Alaska would vote Democratic, Hawaii would vote Republican, and so Congress could vote for both to cancel the political threat of the other out. However, it wasn't necessarily meant to be in 1959, just as it had fallen through before.
What if Hawaii and Alaska did not get statehood in 1959?