At Continental you can work both also, but it isnt as straight forward as working them in your own base. For example, let's say that you are based in IAH for International (HTA) then your line that you bid for the month is for International flights, but you can pick up flights that are in open time (sick calls etc). When picking up flights out of base, you do not have the same rights to picking them up as someone that is in the Domestic base. There are time windows of when you can and cannot pickup out of base.
Flight attendants at United can work either international or domestic, but international requires extra training above and beyond what is required for domestic flights. Once that is finished, they can work either.
Further training is also required if a flight attendant wants to act as Chief Purser (head flight attendant on an international flight).
There is an international program training requirement that lasts an afternoon. You bid for your schedule every month and based on your seniority, or if you can speak a foreign language will dictate what you can get.
Seniority for regular international positions hovers between 10-13 years. Language speakers are basically a grab bag of seniority that runs the spectrum of Italian being quite junior to German being quite senior.
If you cannot hold an international position based on bid results, you can pick up from open time (vacations, sick calls), move up from a domestic trip to an international trip, or pick up a trip from another flight attendant.
That F/A likely lives in MCI and is commuting to CVG to fly the LGW trip. She was riding on the leg MCI-CVG as a passenger or on a jumpseat. She was not on duty. At this time, DL does not schedule a domestic leg prior to an international departure.
This seems to have gotten off topic, I didnt realise it was about aircraft types we can fly, I thought it was about what routes we can fly. At Continental, when you do training, it is on all aircraft types in the fleet. So everyone can fly anything.