We report on the structural and electronic properties of solid-solution films consisting of perovskite band insulators, SrTiO3 and LaAlO3, with a chemical formula of Sr1-xLaxTi1-xAlxO3-delta. Single crystalline films grown by pulsed-laser deposition are fairly insulating below 300 K when having x >= 0.6, while x < 0.6 films exhibit electronic conduction accountable with a variable-range hopping. Room temperature conductivity has a maximum value of 20 Omega(-1) cm(-1) at x similar to 0.2. Hall measurements reveal that the density of the carriers varies as x(1-x) per Ti site up to x similar to 0.35, apparently indicating that La3+ donates one electron to a remaining Ti site. The results are discussed in comparison with the electronic properties of LaySr1-yTiO3 films in terms. of different carrier localization mechanisms.