Any help with my New York City 6-day itinerary?

Day 1:
- Arrival at 13:30, at hostel around 16:00
- Times Square by night

Day 2:
- Grand Central Terminal, Bryant Park
- Top of the Rock observatory, Public Library
- Times Square, Macy's, Madison Square Park
- Empire State Building observatory (by night)

Day 3:
- Statue of Liberty
- Battery Park, Wall Street, Brooklyn Bridge
- Brooklyn Bridge Park (by night)

Day 4:
- 9/11 Museum
- SoHo, Greenwich, Washington Square Park
- China Town

Day 5:
- American Museum of Natural History
- Central Park, Metropolitan Museum (quick visit, 1h max)
- Rooftopbar

Day 6:
- High Line
- Hell's Kitchen / Chelsea
- Leaving back to airport around 15:00

What happens when your flight is canceled?

I'm new to traveling and I want to know as much as I can before I go on my first trip just to be prepared.

What happens if the flight you payed a ticket for gets canceled? Are you entitled to get a new flight from the airline, or do they refund you your ticket?