How to fetch related source and destination Flights from table

Hi My table consists of:

source  destination
LA  BOS
LA  BOS
Seattle BOS
Bos LA
BOS Seattle
NY  Seattle
CA  LA
LA  CA
LA  Chicago
CA  BOS
BOS Seattle

I am trying to fetch if my source either contains boston or seattle and if either my destination contains boston or seattle. so result should look like this:

source  destination
Seattle BOS
BOS Seattle
BOS Seattle

My query does not work:

select source,destination 
from dbo.flights
where source in ('BOS','Seattle') or destination in('BOS','Seattle')

Answer

As @jarlh said in a comment, use AND instead of OR:

select source,
       destination 
from   dbo.flights
where  source      in ('BOS','Seattle')
AND    destination in ('BOS','Seattle')