A horizontal airfoil, at the rear of an aircraft, to which the elevator is attached; usually associated with the tailfin(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "tailplane" in a sentence
"Sudden & catstrophic depresurisation would most likely suck her out & blow her clear of wings & tailplane."
"She was much better at off-the-cuff stuff like the handkerchief over the British Airways tailplane, or the remark that she didn't see why immigrants should get council houses ahead of native British people, or the 'Rejoice!' after the successful end to the Falklands war."
"The Cloud was coming back now, finishing its clockwise tour of the plane, flowing over the tailplane before pouring itself back into a cube."