Vice-president Andrew Johnson and Secretary of State Seward are the answers to your question. But, your question has implications that are incorrect.
Booth planned to kill no one. He planned to kidnap Lincoln and no one else. Many others were planning to kill Lincoln. Late in the afternoon of April 14, 1865, Booth was brought into a plan to kill Lincoln. It was not his plan!!! He was just the assassin.
Booth killed Lincoln. The assassins of Vice-president Andrew Johnson and Secretary of State Seward failed to kill their intended victims.
Because John Wilkes Booth was successful in killing Lincoln, he has been given the credit for the for the planning of all three assassinations. He did not create the plans or organize the personnel for a successful mission.
That does not mean there was no planning. There was an immense amount of planning by a trusted friend of Lincoln's, Edwin Stanton.
John Wilkes Booth
He was hung for assassinating Abraham Lincoln.
john Wilkes booth
John Wilkes booth
jumped off platform after assassinating abe lincoln
monkeys, all the monkeys in the world
Booth went to Ford's Theatre where Lincoln, his wife and their guests were watching a performance of "Our American Cousin".
He is famous for assassinating Abraham Lincoln.
John Wilkes Booth suffered a broken leg when he jumped down to the stage from the Presidential Box after assassinating President Lincoln.
John Wilkes Booth was a very popular and famous stage actor, however, this was not his claim to fame. He was the man responsible for assassinating Abraham Lincoln. And that lead to his ultimate demise.
Because he was a fugitive and he was hiding from the police after assassinating Abraham Lincoln. Then, he was shot in that barn by the local police.
Booth and his group planned to kidnap Abraham Lincoln.