Originally Posted by
Greenie101
what about interline agreements? i was thinking of doing this ATL-FCO on Delta and FCO-Malta on Alitalia. Since Delta and Alitalia have interline agreements, could i get the boarding pass in Atlanta? and not have to recheck?
Not in general, but some pairs of closely partnered (not just members of the same alliance) have such policies, although it might be hard to convince airport agents to follow them at an outstation. YMMV, but do not assume anything on separate tickets; this is not the same as a connection (transit), and currently overnight connections can have different rules.
In the OP's case, If "Tokyo" means a combination of NRT and HND, it definitely will NOT work, even if it's the same carrier.