During a SYD-MEL flight recently, the pilot welcomed us to "our flight across to Melbourne today". When I heard this, I realized that many pilots use that preposition when describing relatively short flight segments. I wonder how across originated in this context. Does it somehow capture the brevity of the flight from the pilot's point of view?

Another interesting one is today. Not just pilots (as above) but also cabin staff often use this when serving a drink, e.g., "Coffee for you today?". Again, I wonder what the "today" signifies. Did they hear that I ordered tea yesterday and need a change of refreshment? What about the other flights I'm taking today? Should I be answering for those as well?

I'd be interested in any comments on these or other spoken peculiarities in informal in-flight use.