  Accreting black-hole binaries change their properties during evolution,
passing through two main luminous states, dominated by either hard or soft
X-rays. In the hard state, steady compact jets emitting multiwavelength
radiation are present. Those jets are usually observed in radio, and when
resolved, their extent is $\lesssim\!10^{15}$ cm. Then, during hard-to-soft
transitions, powerful ejecta in the form of blobs appear. They are observed up
to distances of $\sim\!10^{18}$ cm, which are $\gtrsim$1000 times larger than
the extent of hard-state jets. On the other hand, estimates of the accretion
rates during most luminous hard states and the hard-to-soft transitions are
very similar, implying that maximum achievable powers of both types of jets are
similar and cannot cause the huge difference in their propagation. Instead, we
explain the difference in the propagation length by postulating that the ejecta
consist of electron-ion plasmas, whereas the hard-state jets consist mostly of
electron-positron pairs. The inertia of the ejecta are then much higher than
those of compact jets, and the former are not readily stopped by ambient media.
A related result is that the accretion flow during the hard state is of
Standard and Normal Evolution (SANE), while it is a Magnetically Arrested Disk
(MAD) during transient ejections. The pairs in hard-state jets can be produced
by collisions of photons of the hard spectrum emitted by hot accretion flows
within the jet base. On the other hand, the X-ray spectra during the state
transitions are relatively soft and the same process produces much fewer pairs.
