A hospital spokeswoman said that Carter was feeling "normal" on Wednesday morning.
"His doctors at MetroHealth Medical Center recommended additional observation during the day. He looks forward to resuming his schedule as soon as possible," said MetroHealth Medical Center spokeswoman Christina Karas.
The former president's publisher canceled scheduled book signings in Washington, D.C. on Wednesday. However, no decision has been made about an event planned at a Columbia, S.C. bookstore on Thursday.
Book signings in Durham, N.C. were canceled on Tuesday when Carter, 85, became ill on a flight headed to Cleveland.
Carter's grandson, Georgia state Sen. Jason Carter, said Tuesday his grandfather was doing fine and "resting comfortably."
Carter was on a Delta Air Lines flight from Atlanta to Cleveland when he fell ill. After the plane landed at Cleveland Hopkins International Airport, he was taken to the hospital by EMS crews.
Carter was elected to the White House in 1976. He has spent his recent years pursuing peace and human rights, efforts that won him the Nobel Peace Prize in 2002.
The Associated Press contributed to this report.
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