ensure changing filetypes gets updated statusline if necessary. fix statusline overwrite when using unite with -no-split

autoload/airline.vim

@@ -78,6 +78,7 @@ endfunction
 
 function! airline#update_statusline(active)
   if s:is_excluded_window()
+    call setwinvar(winnr(), '&statusline', '')
     return
   endif
 

autoload/airline/extensions.vim

@@ -4,6 +4,7 @@ function! airline#extensions#load()
         \ let w:airline_section_a = 'Unite'
         \ | let w:airline_section_b = unite#get_status_string()
         \ | call airline#update_statusline(1)
+        \ | unlet w:airline_section_a | unlet w:airline_section_b
 
   if exists('g:loaded_ctrlp') && g:loaded_ctrlp
     call airline#extensions#ctrlp#load_ctrlp_hi()

plugin/airline.vim

@@ -50,5 +50,5 @@ augroup airline
   au!
   autocmd ColorScheme * call airline#highlight(['normal'])
   autocmd WinLeave * call airline#update_statusline(0)
-  autocmd WinEnter,BufWinEnter * call <sid>init() | call airline#update_statusline(1)
+  autocmd WinEnter,BufWinEnter,FileType * call <sid>init() | call airline#update_statusline(1)
 augroup END