#1 arrows looks wrong in power line

It is necessary to install the powerline fonts. In the case of arch use:

$ sudo pacman -S powerline-fonts

and select one of the columns symbols that appear in the help of vim:

:help airline

and then search for let g:airline_symbols.color = to select one of the displayed symbols.

let g:airline_symbols = {}
" powerline symbols
let g:airline_left_sep = ''
let g:airline_left_alt_sep = ''
let g:airline_right_sep = ''
let g:airline_right_alt_sep = ''
let g:airline_symbols.branch = ''
let g:airline_symbols.colnr = ' :'
let g:airline_symbols.readonly = ''
let g:airline_symbols.linenr = ' :'
let g:airline_symbols.maxlinenr = '☰ '
let g:airline_symbols.dirty='⚡'

Note: You must define the dictionary first before setting values. Also, it's
a good idea to check whether it exists as to avoid accidentally overwriting
its contents.

  if !exists('g:airline_symbols')
    let g:airline_symbols = {}
  endif