UNITED starting 01JUL09 will be switching its flight number range on service operated by TACA and LACSA. The new flight number range is UA5300 – 5399, replacing UA4300 – 4399
| Route | TA Operate | till 30JUN09 | eff 01JUL09 |
| Guatemala City – Chicago | TA588 | UA4320 | UA5320 |
| Chicago – Guatemala City | TA589 | UA4321 | UA5321 |
| Guatemala City – Los Angeles | TA510 | UA4385 | UA5385 |
| Los Angeles – Guatemala City | TA511 | UA4352 | UA5352 |
| Guatemala City – Miami | TA320 | UA4319 | UA5319 |
| Miami – Guatemala city | TA321 | UA4357 | UA5357 |
| Lima – Cuzco | TA007 | UA4366 | UA5366 |
| Cuzco – Lima | TA008 | UA4367 | UA5367 |
| Lima – Montevideo | TA041 | UA4371 | UA5371 |
| Montevideo – Lima | TA040 | UA4370 | UA5370 |
| San Jose CR – Lima – Santiago de Chile | TA033 | UA4363 | UA5363 |
| Santiago de Chile – Lima – San Jose CR | TA032 | UA4336 | UA5336 |
| San Pedro Sula – Miami | TA374 | UA4304 | UA5304 |
| Miami – San Pedro Sula | TA375 | UA4337 | UA5337 |
| San Pedro Sula – New York JFK | TA574 | UA4339 | UA5339 |
| New York JFK – San Pedro Sula | TA575 | UA4340 | UA5340 |
| San Salvador – Belize | TA410 | UA4345 | UA5345 |
| San Salvador – Dallas | TA440 | UA4318 | UA5318 |
| Dallas – San Salvador | TA441 | UA4356 | UA5356 |
| San Salvador – Guatemala City – Chicago | TA588 | UA4320 | UA5320 |
| Chicago – Guatemala City – San Salvador | TA589 | UA4321 | UA5321 |
| San Salvador – Lima | TA053 | UA4348 | UA5348 |
| Lima – San Salvador | TA040 | UA4335 | UA5335 |
| San Salvador – Los Angeles | TA522 TA528 TA520 |
UA4303 UA4307 UA4374 |
UA5303 UA5307 UA5374 |
| Los Angeles – San Salvador | TA521 TA531 TA529 |
UA4375 UA4338 UA4308 |
UA5375 UA5338 UA5308 |
| San Salvador – Managua – Miami | TA360 | UA4354 | UA5354 |
| Managua – San Salvador | TA314 | UA4309 | UA5309 |
| Miami – Managua – San Salvador | TA361 | UA4360 | UA5360 |
| San Salvador – Miami | TA310 | UA4362 | UA5362 |
| Miami – San Salvador | TA311 | UA4331 | UA5331 |
| San Salvador – New York JFK | TA570 TA566 |
UA4344 UA4315 |
UA5344 UA5315 |
| New York JFK – San Salvador | TA567 TA571 |
UA4317 UA4316 |
UA5317 UA5316 |
| San Salvador – Roatan | TA380 | UA4346 | UA5346 |
| San Salvador – Roatan – Miami | TA430 | UA4346 | UA5346 |
| Miami – Roatan – San Salvador | TA381 | UA4364 | UA5364 |
| San Salvador – San Francisco | TA560 | UA4333 | UA5333 |
| San Francisco – San Salvador | TA561 | UA4334 | UA5334 |
| San Jose CR – San Salvador | TA310 | UA4362 | UA5362 |
| San Salvador – San Pedro Sula | TA220 | UA4359 | UA5359 |
| San Pedro Sula – San Salvador | TA410 | UA4324 | UA5324 |
| San Salvador – Tegucigalpa | TA374 | UA4355 | UA5355 |
| Tegucigalpa – San Salvador | TA214 | UA4310 | UA5310 |
| San Salvador – Washington Dulles | TA580 TA590 |
UA4311 UA4312 |
UA5311 UA5312 |
| LR Operate | till 30JUN09 | eff 01JUL09 | |
| Guatemala City – Los Angeles | LR640 | UA4351 | UA5351 |
| Los Angeles – Guatemala City | LR641 | UA4386 | UA5386 |
| San Jose CR – Los Angeles | LR604 | UA4391 | UA5391 |
| Los Angeles – San Jose CR | LR605 | UA4390 | UA5390 |
| San Jose CR – Miami | LR690 | UA4394 | UA5394 |
| Miami – San Jose CR | LR691 | UA4393 | UA5393 |
| San Jose CR – New York JFK | LR660 | UA4389 | UA5389 |
| New York JFK – San Jose CR | LR661 | UA4388 | UA5388 |
| San Salvador – San Jose CR | LR671 | UA4382 | UA5382 |