on time - in time

On time - это "пунктуально, соответственно расписанию, в точное конкретное время, без задержки".

In time - это "достаточно рано, до того момента, как что-то сделать, но еще немного и будет уже поздно."

• She arrived on time for her job interview, but barely made it in time to catch the last subway.
• The concert started on time, but we arrived just in time to find our seats.
• He turned in his assignment on time, and in time, he’ll see the positive impact on his grades.
• The flight departed on time, but they managed to board just in time.
• Our train left on time, but we got there just in time to grab a quick coffee beforehand.
• The library opens on time every morning, and I get there just in time to be the first inside.
• Her speech began on time, and thankfully, the microphone was fixed just in time.
• The meeting started on time, but John arrived just in time to hear the opening remarks.
• She submitted the report on time, which allowed her to make corrections in time for the final deadline.
• Dinner was served on time, but the guests arrived just in time before it got cold.

In summary:

    • On time = exactly when planned, scheduled, or agreed upon.

    • In time = with a bit of spare time or before a deadline/urgent moment, often implying relief or urgency.