XBee Pro Antenna Options - do the U.FL antennas have better range than the chip or micro pad antennas?
Antennas don't have "range"!

An Antenna is the interface/converter between the electrical signal that the electronics use and the air, where the signal travels as an EM-wave.

There is nothing in the antenna that defines the range. Sure, the choice of antenna and how you use it influences the range of the system but the antenna itself does not determine the range.

The usable range of a wireless system is determined by a whole list of things like transmit power, RF frequency, receiver sensitivity, required Signal/Noise ratio, datarate, modulation. But also the environment like other equipment using the same frequency band, presence of walls and the materials these walls are made of.

You can select an antenna that has directivity meaning it transmits/receives signals better in one (or more) directions than in other directions. A good example is a dish-antenna which has a very narrow angle at which it can transmit/receive well.

Such a directional antenna can increase the range but it comes at a cost: the antenna needs to be oriented correctly. If you use a directional antenna and do not orient it correctly the usable range of your system might decrease dramatically.