Which actor appeared in the most episodes of the Twilight Zone?

I believe it is a tie:

Burgess Meredith appeared in 4 episodes: Time enough at Last, The obsolete man, printers devil, and mr. dingle the strong.

Jack Klugman also appeared in 4: In Praise of pip, a game of pool, death ship and a passage for trumpet

Additionally, even though he is a much lesser known actor, Cyril Delevanti appeared in 4 episodes, Passage on the Lady Anne, A Piano in the House, The Silence, and A Penny for Your Thoughts. He did not have a leading role in any of those, however. But, several other much lesser known actors appeared in more than 4 episodes. Robert McCord appeared in 10, Jay Overholts appeared in 8, Vaughn Taylor appeared in 5.