Upvote:2
This seems to be very dependent on the airline's policies. Here in the United States, I've flown on a lot of domestic and international airlines (Cathay Pacific, Japan Airlines, ANA, JetBlue, AA, etc.), and most of them allow you to pick your seats during the ticket purchase process. Under those systems, it's beneficial to buy your tickets far in advance so that you are able to pick a better seat.
There are also airlines like Southwest that have no seat assignments and utilize a first-come, first-served seating policy.
However, very special seats like front row or bulkhead seats typically cost more or are a different class (like business/first or premium economy). They require you to buy a different level of ticket or pay extra for being able to pick them.
Upvote:4
The answer to this question is very dependent on the airline.
First of all, note that the front seats are often business class or first class seats. You already know how to get those - by paying more for these seats.
In many traditional airlines, the front rows in the economy class are reserved for status customers and can be reserved ahead of time only by them. During check-in, remaining seats may be assigned to other travelers.
With some airlines, the front seats can be reserved for a fee. This tends to be the case particularly often if the airline offer EconomyPlus or a similar "light" business class.
Then, in some other airline/plane model combination, the front row seats are reserved for travellers with infants or other people with special needs. They will only be available for such travellers.