detect whether quickfix or location list is open.

autoload/airline/extensions.vim

@@ -63,12 +63,7 @@ function! airline#extensions#apply(...)
     return -1
   endif
 
-  if &buftype == 'quickfix'
+  if &buftype == 'help'
-    let w:airline_section_a = '%q'
-    let w:airline_section_b = '%{get(w:, "quickfix_title", "")}'
-    let w:airline_section_c = ''
-    let w:airline_section_x = ''
-  elseif &buftype == 'help'
     call airline#extensions#apply_left_override('Help', '%f')
     let w:airline_section_x = ''
     let w:airline_section_y = ''
@@ -127,6 +122,8 @@ function! airline#extensions#load()
   " non-trivial number of external plugins use eventignore=all, so we need to account for that
   autocmd CursorMoved * call <sid>sync_active_winnr()
 
+  call airline#extensions#quickfix#init(s:ext)
+
   if get(g:, 'loaded_unite', 0)
     call airline#extensions#unite#init(s:ext)
   endif

autoload/airline/extensions/quickfix.vim

@@ -0,0 +1,37 @@
+" MIT License. Copyright (c) 2013 Bailey Ling.
+" vim: et ts=2 sts=2 sw=2
+
+let g:airline#extensions#quickfix#quickfix_text = 'Quickfix'
+let g:airline#extensions#quickfix#location_text = 'Location'
+
+function! airline#extensions#quickfix#apply(...)
+  if &buftype == 'quickfix'
+    let w:airline_section_a = s:get_text()
+    let w:airline_section_b = '%{get(w:, "quickfix_title", "")}'
+    let w:airline_section_c = ''
+    let w:airline_section_x = ''
+  endif
+endfunction
+
+function! airline#extensions#quickfix#init(ext)
+  call a:ext.add_statusline_func('airline#extensions#quickfix#apply')
+endfunction
+
+function! s:get_text()
+  redir => buffers
+  silent ls
+  redir END
+
+  let nr = bufnr('%')
+  for buf in split(buffers, '\n')
+    if match(buf, '\v^\s+'.nr) > -1
+      if match(buf, '\[Quickfix List\]') > -1
+        return g:airline#extensions#quickfix#quickfix_text
+      else
+        return g:airline#extensions#quickfix#location_text
+      endif
+    endif
+  endfor
+  return ''
+endfunction
+

doc/airline.txt

@@ -233,6 +233,18 @@ configuration values that you can use.
   " Note: set to an empty dictionary to disable truncation.
   let g:airline#extensions#default#section_truncate_width = {}
 <
+-------------------------------------                     *airline-quickfix*
+The quickfix extension is a simple built-in extension which determines
+whether the buffer is a quickfix or location list buffer, and adjusts the
+title accordingly.
+
+* configure the title text for quickfix buffers >
+  let g:airline#extensions#quickfix#quickfix_text = 'Quickfix'
+<
+* configure the title text for location list buffers >
+  let g:airline#extensions#quickfix#location_text = 'Location'
+<
+
 -------------------------------------                   *airline-bufferline*
 vim-bufferline <https://github.com/bling/vim-bufferline>