As I inched my way through the 45-minute line to clear customs at Miami International Airport on a recent Sunday afternoon, the sign for Global Entry was a torment. The queue for the U.S. Customs and Border Protection’s trusted traveler program that speeds low-risk U.S. citizens through customs when they return back to the country was ridiculously short in comparison to mine. And all the details on the Global Entry program were still fresh in my mind: I had just heard Kenneth Sava, director, trusted traveler programs, at the CBP, speak at Hyatt’s Insurance and Financial Business Exchange.

At the event, planners and hoteliers listened with interest, and had plenty of questions, as Sava sorted out the four overlapping programs that exist to get U.S. citizens through airports faster: PreCheck, run by the Transportation Security Administration, and Global Entry, NEXUS, and SENTRI, run by Customs and Border Protection.

Here’s a rundown of each, but consider this as you read: Sava himself is a NEXUS member (the least expensive and broadest).

For all four programs, travelers must complete a pre-enrollment online application and, if accepted, make an appointment for an in-person meeting at an application center where they will be asked for proof of citizenship and have their fingerprints recorded.

TSA’s PreCheck: Members use PreCheck lanes to go through security screening at U.S. airports (currently 180+ airports are in the program) and don’t have to remove their shoes, belts, or jackets, or take laptops out of their bags. This program is for domestic airport security and does not help travelers get through customs. TSA says it has 380 locations nationwide where applicants can go for the in-person meeting, far more than CBP. Cost: $85/five years

Global Entry: Includes PreCheck privileges, plus expedited processing through customs at U.S. airports and land borders. First, members use Global Entry kiosks to provide passport and declaration information and then, after collecting their luggage, have a dedicated exit line from the customs area. There are enrollment centers around the country, plus Guam and Qatar. Cost: $100/five years

NEXUS: Includes Global Entry and PreCheck privileges, and also provides expedited processing when entering Canada. This bilateral program is open to both U.S. and Canadian citizens. Applications must be approved by both countries. And, since the in-person appointment involves both Canadian and U.S. personnel, the 24 enrollment centers are primarily in Canadian–U.S. border cities. Cost: $50/five years

SENTRI: Includes Global Entry and PreCheck privileges. SENTRI is focused on land border crossings from Mexico, with dedicated lanes at 11 entry points for travelers arriving in California, Texas, and Arizona. There are 10 enrollment centers in U.S. cities near the Mexican border. Cost: $122.25/five years