hi George & Jörg
thank you for your advice
the code hints & auto completion works now, but it is only for standard SAP keywords.
the fi_tab_type in...
CLASS flightprogram DEFINITION.
PUBLIC SECTION.
TYPES: fi_tab_type TYPE STANDARD TABLE OF spfli.
DATA: flight_table TYPE fi_tab_type.
PRIVATE SECTION.
ENDCLASS.
...seems to be a non keyword. as I understand SAP keywords are like CLASS...DEFINITION. PUBLIC SECTION. etc..
I played around with the Option settings and enabled the "Suggest Non-Keywords from the Text" under Dictionary.
and, when I typed the "fi" word, a screen tip auto appeared. I just press TAB and it auto completed it. So it seems it is this "Suggest Non-Keywords from the Text" setting which makes it work.
thanks for showing me where to edit the options 
Nevertheless, I use CTRL+SPACE also works, just that it shows a complete list of keywords. I could find fi_tab_type there as well.
