select menu option from a file --shell scripting

I have A question regarding the menu in shell scripting. I created a menu in shell scripting. however, in one of the options, I have a list the user can select from but the list is big, so I want the user to select the option from a file. how do we do that?

:select_menu 
cls
echo.
echo                               ====================
echo                                 Main Menu 
echo                               ====================
echo                        1 =Airport 
echo                        2 =Warhouse 
echo                        3 =Parcel
echo                        4 =Other Projects 
echo                       ------------------------------------------------------
echo                       q = Quit    
echo                      -------------------------------------------------------
set /p op="Select  option:"


if "%op%"=="1" goto op1  
if "%op%"=="2" goto op2  
if "%op%"=="3" goto op3 
if "%op%"=="4" goto op4   

if "%op%"=="q" exit



:op1
color 17
cls
echo.
echo                               ====================
echo                                 Airport Menu 
echo                               ====================
echo                        1 =Gotenburge 
echo                        2 =Heathrow
echo                        3 =Brussels
echo                        4 =Kiev 
echo                       ------------------------------------------------------
echo                       r = Return to Main Menu   
echo                      -------------------------------------------------------

set /p a_op="Select airport:"

if "%a_op%"=="1" echo "Contact A.N.OTher" && pause
if "%a_op%"=="2" echo "Contact B.N.OTher" && pause   
if "%a_op%"=="3" echo "Contact B.N.OTher" && pause  
if "%a_op%"=="4" echo "Contact C.N.OTher" && pause    
if "%a_op%"=="r" goto select_menu 

goto op1

:op2
echo you selected Warhouse
color 0a
pause
cls
goto begin
goto :eof

:op3
echo you selected Parcel
color fc
pause
cls
goto begin

:op4
echo you selected Other Projects
color a1
pause
cls
goto begin

:exit

In the Airport Menu, I have 250 airports as an example but I don't want to list all airports, I want the user to be able to check a separate file called Airport_list then choose the relevant option.