With the summer season coming on, many travelers are wondering whether their airline, too, will follow Braniff International into bankruptcy. Airline analysts are optimistic about the outlook for the industry as a whole, but here and there question marks remain.

Republic Airlines and World Airways are "the biggest worry today" in the view of Marc Klee, whose National Aviation and Technology Fund specializes in aviation stocks.

He expects a fat summer travel season, together with an economic recovery, to put money-losing airlines back into the black. But if the recovery fades next year, he would start to worry about a broader group of airlines, among them Eastern, Western, Pan American and the Texas Air group, the latter including Continental, New York Airways and Texas International.

You can protect yourself against ticket risks by buying through a travel agent. If the agent writes the ticket and your airline goes bankrupt, that ticket is automatically good on other U.S. airlines and most foreign airlines. You will usually have to fly standby, which means that you travel only when the substitute airline has unsold seats. But you will fly.

If you bought your ticket directly from the bankrupt airline, it may not be good. Other airlines do not have to accept it, although in Braniff's case many airlines are taking the tickets for a short time.

A free ticket or a $1 promotional ticket will probably not be accepted on another airline, no matter how you got it.

If you're holding a Braniff ticket and decide not to travel, you lose the money. Travel agents do not refund. All you can do is write to Braniff and get in line with all its other creditors.

The no-refund policy may tempt travelers to delay paying for their tickets until the last minute, to be absolutely sure of their vacation plans. But delayed payment runs you into another kind of risk.

Airlines normally charge whatever price prevails on the day you pay for the ticket, which may be higher than it was when you made the reservation. Special discounts often don't last very long. So buying in advance is the only way to nail down a specific fare. (If you buy in advance and, later, the ticket price drops, your agent can rewrite the ticket at the lower fare.)

Ticket prices in general are going up from the rock-bottom promotional rates that prevailed this spring. Braniff was offering sensational bargains, such as two tickets for the price of one, in order to keep the cash flowing in, and competitors were meeting the price. Now, prices will probably rise on Braniff's old routes. Other discounters are also expected to raise their prices in order to survive.

The travel sections of Sunday newspapers often carry cheap-ticket ads for people flexible enough to travel at the last minute. Certain foreign airlines, for example, often discount tickets a week or so before flight times. The same is true for charter tours that haven't sold enough seats.

Undersold charters are sometimes canceled. But travel columnist Jane Morse says that if you buy your ticket 30 days or less before departure, you should be on a flight that goes. Tours are rarely canceled at that late date (although they can be scrubbed up to 10 days before departure).

Discounting is also done for volume buyers. These include travel agencies that specialize in ethnic tours (for example, to Israel, Greece or the Orient) and agencies that serve corporate accounts. If you have a company travel agent, he or she may be able to get you an especially good price.

You may have seen ads for travel clubs that offer special discounts to members. Sometimes these discounts are genuine, sometimes not.

Clubs often sell the remaining seats on package tours at clearance prices. On the other hand, a "low" fare touted in a member's newsletter might be a little higher than a promotional fare of another airline. You might also be getting "25 percent off" an inflated price.

Members of travel clubs should double-check the club's fare offers with a travel agent to see if the agent can get them something better. Between club and agent, you'll have two shots at the lowest price