You should have labeled the thread title as "How to Upgrade to First or Business Class and/or Get Special Treatment Because I am a Pilot." Your intent had nothing to do with jumpseating etiquette. In jumpseating, yes, definitely thank the CA because if he's in a good mood he'll personally ask the FA to seat you up front if there's availability. But if all you want is an upgrade/special treatment because you were too cheap to buy a business or first class ticket and were using a non-first class company standby or paid economy ticket, put on your best smile and flirt with the Chief Purser/Head FA for a minute or so. Always worked for me. But if the FA's a guy, well...haven't run into that situation yet.