The best agencies are often accredited by established trade organizations, such as the American Society of Travel Agents, the Association of Retail Travel Agents, and the International Airlines Travel Agent Network; some states require agencies to be licensed. And if an agent is vague in response to direct questions and doesn't provide a telephone number or address on its Web site, be wary.

As for consolidator tickets, the Better Business Bureau suggests that you contact the airline directly to check the status of your reservation before paying the consolidator: A reservation may not represent a confirmed seat on the flight.

The Better Business Bureau also cautions that many consolidators accept only cash or add surcharges for using a credit card. Always use a credit card to protect yourself against travel scams: Never pay for a plane ticket with cash or a check. Credit cards are covered under the Fair Credit Billing Act, which protects you from unauthorized fees and charges for goods and services that weren't delivered as agreed. In other words, if a travel agent doesn't issue the ticket you purchased, the credit card company will help you recover your losses.