Here's what I always use:
WELCOME
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Ladies and Gentlemen, good morning/afternoon/evening and welcome aboard, this is your captain speaking. My name is xxx and assisting me on the flight deck is first officer xxx. You have a great crew looking after you in the cabin led by cabin supevisor xxx and her team of xxx, xxx and xxx who will take good care of you this morning/afternoon/evening.
We are almost ready to go, just waiting for the last bits of paperwork to be completed, expecting to close the doors and start the engines in the next 5 minutes. The expected flight time today is approximately x hours and x minutes, our routing today will take us away from xxx towards xxx, then passing xxx, xxx and xxx, before beginning our descent over xxx. We will be cruising at xxx thousand feet and weather en route should be good.
The cabin crew will be performing a safety demonstration while we taxi the aircraft to the runway so I would ask you to please pay them your full attention as it is not only for your own safety but also for those passengers seated around you.
I will be speaking to you later on with more information about the flight, the latest weather for xxx and the approximate arrival time. In the meantime please relax and enjoy the service, thank you for your attention.
MID CRUISE
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Ladies and Gentlemen, good morning/afternoon/evening, this is captain ___ from the flight deck again. We are currently cruising at ___ feet at a speed of ___ which is ___ miles per hour and the outside temperature is -40°C.
At present we are overhead ___, our routing will then take us overhead ___ and ___ before we will begin our initial descent into ___ over ___.
The weather in ___ is ___ with a temperature of ___°C and ___. We should be landing ___ minutes ahead of schedule/on time/___ minutes late and be on stand in approximately ___
minutes from now.
Once again Ladies and Gentlemen, thank you for flying ___ today and please enjoy the rest of your flight with us.
AFTER LANDING
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Ladies and Gentlemen, once again your captain. I am delighted to be able to welcome you to ___ on time/___ minutes ahead of schedule where the local time is ___. We will be on stand in a few minutes so please stay in your seats until the aircraft has come to a complete stop, the engines have been shut down and the seat belt sign has been switched off.
Once again, from all of us here on board, captain ___, first officer ___, cabin supervisor ___ and his/her team, ___, ___ and ___ thank you for flying with us and enjoy your stay in the ___ area. Good morning/afternoon/evening
Hope this helps, if you're interested, a French, Spanish, Italian and Swedish version is also available, just do a search.