use code 160 for space to fix rendering problems.

autoload/airline/extensions/branch.vim

@@ -33,7 +33,7 @@ function! airline#extensions#branch#get_head()
 
   return empty(head) || !s:check_in_path()
         \ ? s:empty_message
-        \ : printf('%s%s', empty(s:symbol) ? '' : s:symbol.' ', head)
+        \ : printf('%s%s', empty(s:symbol) ? '' : s:symbol.(g:airline_symbols.space), head)
 endfunction
 
 function! s:check_in_path()

autoload/airline/init.vim

@@ -56,6 +56,7 @@ function! airline#init#bootstrap()
         \ 'linenr': get(g:, 'airline_linecolumn_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ':' ),
         \ 'branch': get(g:, 'airline_branch_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ''),
         \ 'modified': '+',
+        \ 'space': ' ',
         \ }, 'keep')
 
   call airline#parts#define_function('mode', 'airline#parts#mode')
@@ -72,6 +73,7 @@ function! airline#init#bootstrap()
 endfunction
 
 function! airline#init#sections()
+  let spc = g:airline_symbols.space
   if !exists('g:airline_section_a')
     let g:airline_section_a = airline#section#create_left(['mode', 'paste', 'iminsert'])
   endif
@@ -82,7 +84,7 @@ function! airline#init#sections()
     let g:airline_section_c = airline#section#create(['%<', 'file'])
   endif
   if !exists('g:airline_section_gutter')
-    let g:airline_section_gutter = airline#section#create([' ', 'readonly', '%='])
+    let g:airline_section_gutter = airline#section#create([spc, 'readonly', '%='])
   endif
   if !exists('g:airline_section_x')
     let g:airline_section_x = airline#section#create_right(['tagbar', 'filetype'])
@@ -91,7 +93,7 @@ function! airline#init#sections()
     let g:airline_section_y = airline#section#create_right(['ffenc'])
   endif
   if !exists('g:airline_section_z')
-    let g:airline_section_z = airline#section#create_right(['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
+    let g:airline_section_z = airline#section#create_right(['%3p%%'.spc.(g:airline_symbols.linenr).spc.'%3l:%3c'.spc])
   endif
   if !exists('g:airline_section_warning')
     let g:airline_section_warning = airline#section#create(['syntastic', 'whitespace'])

autoload/airline/section.vim

@@ -2,6 +2,7 @@
 " vim: et ts=2 sts=2 sw=2
 
 call airline#init#bootstrap()
+let s:spc = g:airline_symbols.space
 
 function! s:create(parts, append)
   let _ = ''
@@ -19,10 +20,10 @@ function! s:create(parts, append)
       let func = '"'.(part.text).'"'
     else
       if a:append > 0 && idx != 0
-        let val .= ' '.g:airline_left_alt_sep.' '
+        let val .= s:spc.g:airline_left_alt_sep.s:spc
       endif
       if a:append < 0 && idx != 0
-        let val = ' '.g:airline_right_alt_sep.' '.val
+        let val = s:spc.g:airline_right_alt_sep.s:spc.val
       endif
       if exists('part.raw')
         let _ .= val.(part.raw)

autoload/airline/util.vim

@@ -2,6 +2,7 @@
 " vim: et ts=2 sts=2 sw=2
 
 call airline#init#bootstrap()
+let s:spc = g:airline_symbols.space
 
 function! airline#util#wrap(text, minwidth)
   if a:minwidth > 0 && winwidth(0) < a:minwidth
@@ -14,14 +15,14 @@ function! airline#util#append(text, minwidth)
   if a:minwidth > 0 && winwidth(0) < a:minwidth
     return ''
   endif
-  return empty(a:text) ? '' : '  '.g:airline_left_alt_sep.' '.a:text
+  return empty(a:text) ? '' : s:spc.g:airline_left_alt_sep.s:spc.a:text
 endfunction
 
 function! airline#util#prepend(text, minwidth)
   if a:minwidth > 0 && winwidth(0) < a:minwidth
     return ''
   endif
-  return empty(a:text) ? '' : a:text.' '.g:airline_right_alt_sep.' '
+  return empty(a:text) ? '' : a:text.s:spc.g:airline_right_alt_sep.s:spc
 endfunction
 
 if v:version >= 704

t/section.vim

@@ -47,13 +47,13 @@ describe 'section'
 
   it 'should force add separators for raw and missing keys'
     let s = airline#section#create_left(['asdf', 'raw'])
-    Expect s == 'asdf > raw'
+    Expect s == 'asdf > raw'
     let s = airline#section#create_left(['asdf', 'aaaa', 'raw'])
-    Expect s == 'asdf > aaaa > raw'
+    Expect s == 'asdf > aaaa > raw'
     let s = airline#section#create_right(['raw', '%f'])
-    Expect s == 'raw < %f'
+    Expect s == 'raw < %f'
     let s = airline#section#create_right(['%t', 'asdf', '%{getcwd()}'])
-    Expect s == '%t < asdf < %{getcwd()}'
+    Expect s == '%t < asdf < %{getcwd()}'
   end
 
   it 'should empty out parts that do not pass their condition'

t/util.vim

@@ -17,12 +17,12 @@ describe 'util'
 
   it 'has append wrapper function'
     Expect airline#util#append('', 0) == ''
-    Expect airline#util#append('1', 0) == '  > 1'
+    Expect airline#util#append('1', 0) == ' > 1'
   end
 
   it 'has prepend wrapper function'
     Expect airline#util#prepend('', 0) == ''
-    Expect airline#util#prepend('1', 0) == '1 < '
+    Expect airline#util#prepend('1', 0) == '1 < '
   end
 
   it 'has getwinvar function'
@@ -40,8 +40,8 @@ describe 'util'
   end
 
   it 'should ignore minwidth if less than 0'
-    Expect airline#util#append('foo', -1) == '  > foo'
+    Expect airline#util#append('foo', -1) == ' > foo'
-    Expect airline#util#prepend('foo', -1) == 'foo < '
+    Expect airline#util#prepend('foo', -1) == 'foo < '
     Expect airline#util#wrap('foo', -1) == 'foo'
   end