at nearly the check-in time

[keannu]

[FONT=&#48148]At the check-in counter, I found I hadn't brought my passport...[/FONT]
[FONT=&#48148]I was lucky again, I arrived back at the airport at nearly the check-in time. My airplane was overbooked. so I got an upgrade for my seat to a business one. I could use comfortable service in the flight to Tokyo. [/FONT]

Are the underlined correct?

 

[Tarheel]

Say:

I got an upgrade to business class.

 

[tedmc]

I arrived at the airport in the nick of time just before the check-in counter closed.

 

[Tarheel]

I would say:

right at check-in time.

 

[emsr2d2]

I'd say "just as checkin was about to close".

"I could use comfortable service" isn't natural. Try to reword it.

You weren't in a flight; you were on a flight.

 

[keannu]

I'd say "just as checkin was about to close".

"I could use comfortable service" isn't natural. Try to reword it.

You weren't in a flight; you were on a flight.

What about this?

I could enjoy comfortable service on the flight to Tokyo.

 

[emsr2d2]

Service isn't comfortable or uncomfortable. It's good/bad/great/terrible etc. You can say you had a comfortable flight - that refers to the seats (or, in business class, possibly the beds).

 

[tedmc]

You can say that the service (and amenities) provided in the business class is more personal/higher standard/better/enhanced.
The passengers feel comfortable as a result.