There are 2 UAL 744's, one at PMI and one at TFS. As posted elsewhere flight times match, in some cases, MON's schedule...and yes, they do ferry back out empty to return full.
26/09 UA2281 PMI BHX 1120 1255
26/09 MON951 PMI BHX 1120 1255
27/09 UA2285 PMI MAN 1100 1245
27/09 MON533 PMI MAN 1100 1245
28/09 UA2286 ALC LGW 1210 1350
28/09 MON263 ALC LGW 1200 1340
29/09 UA2281 ALC LGW 1330 1510
29/09 MON263 ALC LGW 1330 1510