  We present low-temperature measurements of the low-frequency $1/f$ noise
arising from an ensemble of two-level fluctuators in the oxide barrier of
Al/AlO$_{x}$/Al Josephson junctions. The fractional noise power spectrum of the
critical-current and normal-state resistance have similar magnitudes and scale
linearly with temperature, implying an equivalence between the two. Compiling
our results and published data, we deduce the area and temperature scaling of
the noise for AlO$_{x}$ barrier junctions. We find that the density of
two-level fluctuators in the junction barrier is similar to the typical value
in glassy systems. We discuss the implications and consistency with recent
qubit experiments.
